I am setting mine up to have two servos in the flap/brake servo bay. I thought about putting two mini servos in there, but was able to rig two standard sized servos in the bay. I had to do some creative mounting but got it worked out. I'm planning to have to use a Matchbox to coordinate the three flap servos.

The center flap will probably be plenty for a functional flap, but I agree, would be better to see the true scale flap arrangement.