The only thing I've seen take an Ostie hit and live (and isn't a bomber) is the Il-2. Bombers can take 2-4 hits sometimes, depends on where the rounds land.
The best sight is not to use the sight at all, frankly. The sight is only useful for when someone is basically coming straight at you. Anything resembling a crossing shot probably has 2 or 3 times the amount of lead that the gunsight can give... you need to basically aim a half-screen in-front of the target to get correct lead even at D1.0
The thing to do is, go offline and record yourself shooting at drones for a bit, then watch it in the film viewer. Note where you were aiming and jump into the target aircraft to see where the rounds were actually passing (usually well behind) and adjust your technique. Remember, the drones are easy targets too, 200mph, 3,000ft and ranges of only D1.0 (if you are directly under them). Anything faster than that, or at longer range, and you need even more lead on them to even be close.
