Waffenträger Pak 43 with full interior (Trumpeterer 05550)

I am currently working on the Waffenträger, which I will depict with a full interior.
This includes fuel tanks, transmission, engine, ammo storage and most importantly, getting rid of the thick roof walls (way too thick) and replacing them with thinner styrene plastic. Also all hatches will be cut out and replaced by movable pieces.

I am looking forward to help in terms of scetches, ideas, hints, critique, and much more, as this is, due to the lack of photos, quite a difficult project, especially since I am a Finance guy and no Engineer, so fiddeling around with the engine and guesstimating about proper ositioning of various parts of it is not so easy.

Cheers, have a good one.