Hi Mike, firstly to line the wheel wells with strips of balsa make your own long strips up from balsa cut from accross the balsa sheet, not along it. The balsa will bend very easily to the diameters you require if you soak them & bend them accross the grain, not along it.

Secondly, why bother? Air pressure build up may be an issue with fast flying turbine jets but for a slow flying electric model you seem to be spending a lot of effort fixing a non existant problem. Most full size aircraft just have big, open wells anyway so it will certainly look more scale like than neatly tailored pockets for the gear.

Do make sure you make them the correct shape, the 3 view will show you how. - John.