There is a trick to flying good buff formations, and it involves flying from the gun positions (preferabley nose gun). I'll try to post the complete treatise on this when I get home, but the gist of it goes like this.
Once you're planes are all airborne, Lead sets and announces climb speed (145 works good for B-17). He then backs off power by 10 to 15% from full; this gives others something to work with. Everyone else goes to the nose gun after setting climb speed and engaging autopilot. You then stear with rudders to hold you position side-to-side to the leader, and throttle to hold verticle position. Remember that auto-climb raises or lowers the nose to maintain speed. Throttling up will cause the nose to rise to maintain a set speed; throttling back will cause the nose to drop.
If you find yourself to far behind lead, set a climb speed a few miles per hour faster than lead and use throttle to maintain the same altitude as lead. The plane will speed up, closing the gap. Once you're approaching the desired separation, reset climb speed to what ever lead has set. The nose will try to rise to kill your speed, so just throttle back.
Now, why does this work? Well, it's relatively easy to get two planes headed in the same direction. What's hard is to match speeds (and there fore zero-out closure rates). Once you have everyone in close formation, you can engage any enemy (remember, you're already in the guns, and using outside view to scan and watch your position in formation) for several minutes without the formation getting all strung out. This is because the autopilot will do most of the work of maintaining your position.
I know this sounds counter-intiutive, but it works. The Buccs regularly keep large formations (6 to 12 buffs) in tight formations, fending off attacks while holding it. Hope this made sense to people. My other write up on this is much more comprehensible.
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Sabre (a.k.a. Rojo)