Hi Lynn,
I just finished the cabinets in a 53 Flying Cloud. I used 1/2 and 3/4 oak
plywood for the walls with oak face frames to support drawers and doors.
Using the old walls for templates is iffy as the curves of the wall seem
vary enough to require individual fitting. Use a pencil and various size
washers to trace the exact curve on each panel.
I have used the Kreg system and it worked great, much easier than the
biscuit system.
Good luck on your project and if you need any help or pics email me direct.
Bob Patterson