Ok, where to start, well, let's cover the bomber gun thing:
Bomber guns are effective out to about D1.4, so open up early with at least short bursts. that makes the enemy avoid and makes it more difficult for him to line up (as he has to stop avoiding in order to do so). Set your convergence in the hanger out to D650 (max). Be very good at switching gun positions too... lots of the best anti-bomber guys will take advantage of the limited traverse rate of guns or the lack of knowledge of the different positions. They'll make a fake attack, then dance around you to get you confused as to which position you should be in, only to then slip right inbehind and blast you while you are still fumbling around trying to get into a gun to shoot back. Remember you can jump to F3 view in bombers too, it allows you to see around better. You can do it from a turret also, so you can both see better, and swivel the turret to look around.
Now, on the Ostie, the lead you need is HUGE. For example, try this, go offline and start shooting at the drones. Turn on the video recorded (Alt-R) and tape 30 seconds or so of you trying to shoot at drones. Limit it to a single drone (pick a name). Then, play the video back and jump into that plane and watch where your rounds were passing. Chance are they were WAY behind. I found that at D1.0 and targets at only 200mph (the drones), your lead needed to be more than a half screen width. The sight on the Ostie is essentially useless because of that. If can only help with elevation at best.
One trick I know is used is to use your mouse as a pointer. Move it to the center of the gunsight on the Ostie, then set your head position high enough so you can see over the belt of armour. Then, fire away, using the mouse to know your center point. You can also test things offline by using the constant computed gunsight (turn it on). You need to have padlock turned on also and then you can select targets from the Ostie and it gives you an aim point to fire at. I found that point to still only be about half what I needed to actually lead (after watching tapes of my shooting from the targets perspective).
It's more art that science though, but hopefully this helps.
-Soda
Aces High Trainer Corps.
The Assassins.
