6, 7 and 8 barreled in the nose was pure experimentation, in fact I beleive the leader of the fighters Addi Galland thought it was a great idea, more expllisve power to bear on the US bomber forces but again through the testing the wepaon would vibrate so badly it would cause severe damged to the nose superstructure, and thus not even being an accurate weapon even with the multi-barrel gatling gun effect. seems to me it would purely be a crew enlightening weapon only. the same idea though with more success was ZG 26's use in the filed/air of the 5cm BK weapon. a terrible weapon if accurate against US Heavies but to steer away safely from US escorts ? .......... not a chance in the world. At some stage in 44 ZG 76 used this long thing against Soviet armor.
singles or twins -rockets which was the standard under each wing, this revolved around experimentation in the ZG's of course what is the recommendation in the booklets produced now and war time were carry overs by the ZG's this is what they thought or wished for but never happened in reality. triple rocket launchers were too heavy that was found easily enough when engaged by US fighters from the rear, the Me 410 never stood a chance nor the older Bf 110G-4 armed in similar fashion with heavy cannon and underwing rockets.
as far as I can observe neither the A or B multi-variants of the 410 ever had 3cm Mk 108's in service only by the test Kommando's, they did have shortened barreled MK 103's installed with muzzle brakes in the lower nose housing. the ballistics were far from effective against the US bomber formations and as a result though again ZG 26 and 76 used many different combination's of this 3cm and 2cm weapons packages the 2cm seemed to be the preferred weapon of choice in 4-6/8 combination's in the nose, under the nose and the waffen pod in the belly.
By the summer of 44 it was all over for twin engines the pilots off to single engine JG's which they really knew nothing about to engage fighter vs fighter activities, the ZG crews had been wiped off the face of defense of the Reich in repeated almost daily engagements with the bombers, not that the bomber gun fire was the problem but being chased and or broken up attacks by the P-47 and later P-51 fighter pilots