CM, in my experience the center section glassing is typically enough strength even when the servo cutout is right there. You don't need 6 oz cloth for that. I used to use a 5" wide strip of 3 oz bias cut, and it was plenty strong

However, the wheel wells present a compromised bottom sheet and believe it or not, I've had sheeting cracks at the wells (3/32" contest balsa to boot, back in the day). It is definitely a good idea to add 1 1/2 oz, 1 1/2" wide (bias cut is better) cloth strips around the cutouts. If you take a few moments and think through the loads the wing will see particularly when landing and/or snapping (not at the same time we hope, lol), and add some internal strips of glass, you'll build a wing for practically any rigor.