Necro'ed the thread because there are two more interesting simulations below:
https://www.youtube.com/watch?v=vporVkAUvbM
https://www.youtube.com/watch?v=EBPWS3WJ1b4&t=7s
And it confirms my assumption about how tough T54's hull really was vs. early Cold War projectiles (if anything I was proably too lenient on the 20 pounder). T-54 can easily kill early Centurions, although the Mk5 onwards should be way tougher and need HEAT ammunition.