I'm also in the process of building a DB from BlueJay. I installed the Hayes Slimline 12oz as described above, I agree that the 16oz would probably fit but it would be very tight. I decided to buy the foam core for the wing from Dynamic Balsa rather than build up the wing that came with the kit. If I manage to build this kit true and it flies well, I'll probably build up the wing later and install retracts. I'm also planning to us an OS55AX so I'm hoping this configuration will help control the weight.