Bag The Hun uses a 1″ hex grid which is about the size of the 2p piece here.
Looking at these the 1:300 FW 190 looks about the right size for a gaming piece, as does the 1:600 B-17. If this was a commercial boxed game I wouldn’t be surprised to see the asymmetrical scales but that doesn’t sit right with me on my own project.
Whilst the 1:600 probably is a more realistic overall scale to convey the distances involved between aircraft on the table the Focke-Wolfs are simply too small. In terms of where to compromise, I’d rather have the larger Fortresses than the smaller Focke-Wolfs.
Conclusion: I’m going with the 1:300 scale aircraft and, consequently, a 2″ hex might be worth investigating.
Update: Due to low stock levels, I’ve had to find an alternative source for the aircraft.