john 1)----- 1/8 inch plywood for ribs
2)I use 3/8 by 1/4 inch hardwood rails one by one I add them in and expoxy each one in forming a stack .(both sides ) yes it will be two big for the gear to fit in , you add them in the best possible position and then sand back a gap making sure you have enought rail to screw in the retracts
3)after they are dry , I sit the retracts in them to see the places of contact .Then you gradually remove the contacts areas with a dremil tool sander . Do this gradually so you do not remove too much wood .
4)when the sanding is completed I coat the rails with one more coating of expozy
Remember I start with a good foundation , fiberglass the everything visable and in reach of the retract bay area , this will add strength to you foundation
5)Test the gear to make sure they dont bind before you screw them in , also I prefer toe in so I make sure the have it when adding the rails and sanding