angle of bow

[Hitman]

i was under the impression that range does matter in the slightest, it only effects the time till impact on the stopwatch. you will notice that when u adjust the range none of the torpedo settings change.

That's correct. Range measuring is useful only to know if the target is out of reach and to get speed. But other than that the triangle formed by your sub, the target and the point where torpedo impacts is proportional, the longer the distance to target, the same proportion longer all three corners, so by constant speed of both target and torpedo the impact point remains.

and how degrees for AOB can u afford to be out on say a 2000m shot?

As many as, given the range to target, would set the enemy ship out of the torpedo's path. You should be able to calculate it using distance to target, target length and sinus