The only real issue I found was that the gunshield cut-out was not centered on the guntube. Rest of the kit went together almost by itself

Areas needing extra detailing were the backs of the wheels (where the brake drums should be) and the towing hook arangement. Further I decided to replace the gun shield M2.5 bolts with bolts M2 and the rivets for ones one size smaller (if someones needs some extra rivets just PM me).
Waiting on the supplies to arrive, I started on the detailing of the wheels. I replaced the wheel bolts by threaded rod and added nuts as on the actual piece. As said, the inside of the wheels is not detailed and the keeper ring for the bearing and its 4 bolts are in plain view. On this side the brake drum should be visible. The actual brake drum is a steel casting with distinctive reinforcement ribs, 5 tubular turrets and a larger turret for the brake actuator which are integrated in the ribs. The left and right drums are identical.
My brake drum is entirely made from styrene. Shape is pretty straight forward, base is a styrene disc 60mm in diameter with a cut-out for the wheel axle. A rim was added 3mm high. Ribs (1mm strip) and turrets (5mm tube) are 6.5mm high. Center of the drum is a tube 27mm in diameter (actually build up from strip styrene). The actuator turret is 12mm high and 6.5mm in diameter.
I only have to flesh out the bottom of the ribs for a more fluent transition as on the real casting. The brake lever axle brackets were replaced by styrene ones. The one that will be beside the brake lever has a fixture for the brake lever ratchet.
The tear shaped mounting plate is actually not part of the brake drum but is on the real gun welded to the wheel axle. Nuts (M1.6) will be added later (hope they will arrive next week). Below a shot of all components in place. I might have to shave some material from the 4 bolts on the bearing cover to move the drum more towards the wheel. Next will be the brake axle itself, the actuator arms on the brake drums and the actuator rods.