turret are the mantlet shape and width and the too-big hatch opening in the cupola. Also, the gun ring hatch used on the T23 turret was a low-profile type to allow the TC to see OVER the gun ring hatch to the left of the cupola. It was a very low ring, and the closest HB came was in the M4A3 75mm kit. THe low-profile hatch can be identified by the taller apearing pintle for the .50 BMG. The pintle actually was the same height; the lower gun ring made it look taller.
Gaston, building up the hull with a strip of .060" plastioc to set the width, as Konrad did, and then filling in with an epoxy paste or putty like Miliput and blending the contours might be an alternate to cutting the hull and spreading it. Either will work - it depends on whether you are more confortable as a carpenter or a sculptor.....
