Bazooka should have 80mm of pen.
What why?
Just so you can penetrate the Tiger? 

My brother in Christ, either use explosive pack or shoot at the top of the tank.
The M1s should, the M9s are fine as they currently are. Also, swap the M1 in Normandy out for an M1A1 because the M1 was retired by that point in the war.
No because that is the actual penetration value for the M1 Bazooka using an M6A1 rocket. Even if you argue the M1 should have M6 which had been replaced by M6A1 earlier in the war, it should still pen 76mm of armour instead of 60. 60mm is simply just an incorrect value.
Armour penetration value is bullsh*t.
You can’t really measure it by shooting a rusty iron piece.
Then why not nerf the Panzershrek into the ground? Or give the PTRS 10 bajillion mm of penetration? Devs have decided on this being the standard for every other AT weapon, so the same should apply to the M1.