A reply comment on the Grant/Lee i think is in order:
I remember talking with my former neighbor about this tank and some of its faults in combat, He was pretty emphatic about some of his dislikes:
1. His major dislike: He said that the ideal of riveted armor was sheer lunacy. When the heads of those bolts were hit by smaller caliber shells that wouldn't penetrate the armor, the inertia of the hit would cause the inside head to separate and fly around the inside of the tank, causing injury and sometimes death to the crew members. He even stated that they were going to continue the practice on the sherman, and had actually made some with a riveted or bolted front armor skirt, until the Grant /Lee convinced them to stop doing it.
2, That corner cupola gun: since you couldn't do much with it but attack from a limited arc to the front, if you were engaging another tank you had to practically turn the whole tank in that direction to get a shot. And due to its location on the hull, you couldn't use the gun to fire over an embankment: almost half the tank would be subject to getting hit by another tank if you tried it.
3. The side door to the tank interior located in the sides: although they made them heavy enough to withstand some hits, enough hits could distort them just enough to make getting out in an emergency a tough enough task.
his biggest comments were that if it supported infantry only, and didn't have to slug it in a tank battle, it was okay.
I'm not a tanker, but it certainly doesn't sound good to me...