Secondary armament will be a 128mm in a flexible mount in the turret, 2x MG-15s in the front glacis plate and 2 quad 20mm flak turrets on the rear deck.
I've a pic of the Churchill in the engine bay I'll find that.
PzIII munitionspanzers would be good, there is hangerage for a couple of BMW bikes in the rear too. About 75 SDKFZ-9s to tow it perhaps?