There are darn few heavy tanks before 1942.
maybe 6 of these or a few more including prototypes?
I forgot your concept of a heavy tank is quite unique, In my vernacular, as well as everybody else in 1936, a mkIV is a heavy tank. thats certainly how the Heer described them. Dropping everything for MKIV option means basically that the Heer fights Poland and France with no more than 250 tanks....in other words it loses the war before it starts. Sure, move to develop the mKIV after June 1940, but thats raises the issue of "who knew they were going to win with such style"
4X2 trucks work for crap unless you have really good roads. Not a guarantee in Western Europe let alone eastern Europe (and that is before you hit the Russian border.)
So you need 4X4s or 6X6s. 4x6 often don't make it. And to really last they have to be over-built.
Its an often quoted piece of misinformation that Half Tracks and 4x4s in Russia were more reliable and than the lighter 2x4s. Not significantly true (at least for vehicles with a military origin). ive read that a Half Track cost as much as 5x the cost of a basic 2x4, yet its life expectancy in Russia was not 5x, it wasnt even 2x. I expect the same was true for the 4x4s.
Russians used American trucks 43-5 and expended nearly 350000 of them to wastage. Despite their "over engineering", they dont put up with the abuse much better either. There was really only one way to overcome the wastage and that was to build more, doesnt matter what type, though the German later war tracked artillery tractors are a notable exception (RSOs. These are the exceptions to the rule. They were as cheap as chips, had a simple track system based on an existing chassis of a type already in service. It doesnt get better than that. The track system was able to cope with Russian mud and snow because of its wide tracks and no return rollers, it had exceptional reliability, ease of maintenance, and all terrain capability to boot. The US equivalent, the M4 would not be able to fulfil the same role because it used a too complicated...and therefore far too expensive to build in quantity... track system.....the Soviet STZ-5 was better, but still used a return roller system that at least had wider clearances. The RSOs four road wheels per side, all in a single line as part of a "slack-track" system with no return rollers, comprised a much simpler...and therefore much cheaper.... suspension system
that was cheap to build and easy to maintain, much more able to handle the rasputitsa mud season and Russian winter conditions, without mud or snow freezing between the wheels of the complex overlapping/interleaved Schachtellaufwerk suspension systems that German half-track vehicles like the SdKfz 7 possessed.... ) are an exception to this statement. They were excellent and the stand out in the crowd.
Numbers gives you the ability to maintain and lessens the wastage rates due to breakdowns. A broken down axis truck is usually an effective loss....you have to burn it due to partisans usually...doesnt matter if its got chrome plated grease nipples, or is a US type (see below)
The American 2 1/2 ton truck was rated at 2 1/2 tons payload cross country or "off highway". On Highway it was rated at a 10,000lb payload. It was also rated to pull a 7,500lb trailer/load on highway and 4,500lbs off highway.
An International Harvester K7 (commercial) 1941 2 1/2 ton 4X2 was rated at 5,000lbs on high way and 7,000lb off highway. A big difference was the IH had a 5 speed gear box while the standard military 2 1/2 tonner had not only the 5 speed but a 2 speed transfer case. Net weight for the 6X6 was about 2,000lbs heavier (over 10,000lbs)
Russians used these and other US types. It would be wrong to say they were not very successful , but there is no significant difference, long term to the wastage rates of these vehicles, to well designed lighter types. If youve got the luxury of having the worlds largest motor vehicle industry, you will have both the numbers and the quality, but if you have to make a choice, numbers is the way to go....
You need a certain amount of half-tracks as gun tractors or a certain amount of full tracked gun tractors. You probably don't need the variety of different models of 1/2 tracks the Germans had though.
For a nation with problems like germany, Id put tracked capability as "nice to have" rather than "essntial", except if such capability was at little or no cost to numbers. . Having the all terrain capability is nice to have, but having the numbers, in a rationalised fleet is a far more important imperative. German Halftracks and artillery prime movers found they could not operate in the winter conditions of Russia. They were just too over engineered to put up with the primitive conditions. If there were more trucks, on the days that movement was possible (some days in Russia during midwinter, you would be down to your shirt sleeves according to my father) you made hay whilst the sun shone. if you have more light vehicles, as opposed to less tracked vehicles, you are going to be relatively better off by far because of numbers.
But then a lot of European countries tried to make up in "fripperies" what the Americans did with big engines.The standard American 1/2 tracks using engines of the size and power that the Germans used in their 5 and 8 ton 1/2 tracks.
American equipment was better quality and
more plentiful, hence it had a lower attrition rate, because it could be maintained more effectively. Retain the numbers, and you have a better chance at keeping your motor pool in better order. Something worth considering for the east...a better sand more reliable sized motor pool would have given the germans some spare capacity to repair and extend the road and rail networks and thereby reduce the wastage still further, so that their lighter types would have been less of a problem still. Germans started with good numbers, but rapidly fell away because many were not of a military standard and they just didnt really have numbers given the size of their force structure. and it was not possible to maintain the park properly. It became a vicious circle. A poor standard of MT, too many types, too much reliance on non military types, not enough capacity to even keep up with basic logisitic needs, no capacity for infrastructure recovery...it just fed off itself.... They needed fewer types and designed to a military standard...forget the US centric all terrain capability...the US Army has never been tested like the heer was in Russia. and more secure rear areas. When not given that situation, US equipment was no better (or not significantly so) than any other form of MT. In the snow it got just as stuck as any other nationality.
The only exceptions that really were dogs to this are the French and German commercial vehicles that were press ganged into service after the war broke out. These really werent comparable, but then there would have been less need of them if the military production was better organised. less types, better supply, and then you arent relying on crappy French Trucks in the depths of a Russian winter.