Right now, you have to HIT the tiger with 500lb bombs, and get within 3 ft with 1000lb bombs. 2000lb and up, the splash damage will be enough to kill it if you are a decent aim. But 500lbs of HE is 500lbs of HE, the 30mm or so of armor on top of a tiger isn't going to stop that.
Also, it appears that bombs won't even knock of the pintil, or destroy the tracks of ANY tank. I ask to have that rectified as well. Even the HE shells from tanks should do that, I mean 6lbs of explosives will take a pintil gun off in real life.