I've been flying the Hurri IID a lot the past two camps. I'm at the point that I can smoke a Panzer or T-34 on the first pass (two rounds which the IID fires simultaneously) and kill him on the second pass. Four rounds per kill. Of course I miss half the time

Shermans have been slightly tougher for me and I havent really had occasion to hit a Tiger yet.
Angle doesn't have to be that steep. 30-40 degrees seems to do it but you want to hit at, or just behind the turret.
Also, in most cases, even if friendlies have been straffing with mg's you'll get the credit for the kill.
One last thing, the IID is highly susceptable to ground fire, even pintle guns. While flacks would be easy kills, unless they don't see you coming keep your distance.