I'll not comment further on potential other carriers, and instead try to bring us back on topic.
Given Ark Royal's need for a refit in 1942, perhaps we're most likely to next see the 1943 CAG you propose. How big of an air group would you see?
I'll come back to this after highlighting a few other things.
Would Ark Royal keep her two full length hangars or like the Implacables sacrifice half of the lower hangar to workshop, spares and accommodation space?
Not sure what you mean here.
When the Implacables were designed in 1937 the first request was for more speed requiring new machinery. The second request was for more aircraft. So the airgroup was to grow from 36 Swordfish/Skua sized aircraft (36 ft long) to an eventual 48 Albacore sized aircraft (40ft long).
Contrary to popular opinion the reason for the half sized lower hangar was not to generate space for accomodation etc. It arose because the hangar of the Illustrious class had to dropped by a deck to ensure adequate stability within the 23,000 ton Treaty limit. At its forward end it then ran into those boiler uptakes I referred to in earlier posts which had run under the hangar deck in Illustrious. That caused it to have to be only half the length. A new full length hangar was then added on top. Then, again for stability reasons, the hangar height in both ships had to be cut to 14ft. Indomitable had the same layout but managed to retain the 16ft height in what became the lower hangar. But her upper hangar was 40ft shorter meaning her designed aircraft capacity was 45 Albacores (although for simplicity for planning purposes the Admiralty in 1944/45 treated her as a 48 aircraft ship like the Implacables).
A side effect was that, given the lower hangar's depth, some space was available forward of those boiler uptakes which was used for accomodation etc, but that simply replaced what had been lost by lowering the hangar deck in the first place.
These later carriers operated up to 81 aircraft, but I have to assume in a solely short-term pinch due to limited fuel, ordnance and space.
A lot changed between 1938 and 1945 with the Implacables.
Firstly, as noted above, they were designed around a hangar capacity of 48 Albacore sized aircraft (33 in the upper hangar carried 3 abreast and 15 in the lower hangar carried 3 abreast). By 1945 the airgroup contained 40-48 Seafires. [Indefatigable always carried about 9 fewer aircraft than Implacable for reasons not clear to me. There were design differences between the two ships so this might have had an effect. There was also a shortage of Seafire F.III (as opposed to LF.III) in 1945 with which one of her squadrons was equipped. And Implacable was a very happy and efficient ship]
Seafires were shorter than Albacores (30ft v 40ft) and could be packed into the hangar 4 abreast, instantly offering an increase in aircraft capacity.
And in 1945 all the British carriers were operating constantly with deck parks so allowing an increase in aircraft numbers even further. Deck parks, while not unknown in 1940/41 (see Taranto) were not so common.
The petrol capacity of the Implacables was 94,650 Imp Gals. So nearly double that of an Illustrious class (50,000 gals) and not far short of that of Ark Royal (100,000 gals). And in 1945 in the Pacific the carriers were topping up their fuel supplies every 2-4 days from tankers of the fleet train (these ships were carrying mixed loads of furnace fuel oil, diesel and petrol) in the same pattern as the US TF38/58. So initial fuel capacity was less of a problem.
As for ordnance, there were fewer strike aircraft aboard in 1945 (only 21 Avengers) while the Fireflies only used rockets. And the Seafires were only used for CAP during Operation Iceberg while they flew with drop tanks in July/Aug so had no call for bombs or rockets. Add to that, magazines were able to be refilled from ships of the Fleet Train during those replenishment at sea days.
Compare those operations with Ark in 1940/41 operating close to RN bases at Scapa or Gibraltar where she could pop in, refuel, rearm pick up replacement aircraft etc. She would rarely be more than a few hundred miles from a friendly port, not the thousands seen during Pacific operations in 1945.
Assessing Ark's possible aircraft complement is not so easy as in one of the Armoured carriers. Her hangars were 2ft narrower. It makes for example fitting Seafires 4 abreast difficult as it reduces working room below the usual RN 1.5-2ft minimum. The lifts were within the hangar space itself and took up about half the width, allowing for bulkheads, machinery etc. So you lose about 4,500 sq ft of hangar floor (the lifts in Illustrious/ Implacable were outwith the hangar space). Just how each aircraft types could be fitted around those, and other hangar furniture like fire curtains, would be a pen and paper exercise with some detailed plans.
So back to your first question. Ark's capacity from 1942 onwards.
What we do know is that her designed hangar capacity on completion was 60 Swordfish / Skua sized aircraft (36ft long). By 1941 her capacity was about 54. That seems to me to be easily explained by her having replaced 36ft long Skuas with 40ft long Fulmars. 24 Fulmars carried 3 abreast occupy an extra 32ft of hangar length compared to Skuas forcing a reduction of a minimum of 3 Swordfish before figuring in fitting them around lifts etc, which clearly cost another 3.
On the one hand Martlets (29ft long) & Corsairs (34ft long) are smaller than Fulmars, but Albacores/Barracudas/Avengers are all 40ft long. Fitting 3 Avengers in the hangar abreast is tight (19ft folded = 57ft leaving 3 ft - a bare 9in around them compared to 15in in the Armoured carriers). Fitting 4 Martlets abreast (14ft 4in each) was probably impossible as working room comes down to about 6in. So would it have been done in practice? Who would have thought a couple of feet in hangar width could make such a difference!
And then what effect would deck parks have on her aircraft capacity?
So my answer at the moment is I really don't know what Ark's aircraft capacity could have been after 1941. I doubt anyone else does either without a large amount of research and some detailed plans of the ship.
