Finished jig. Removed brackets on D. All square, measurements all good!
Started marking up foam for Centersection. Was convinced for a while I didn't have enough 1" H45, (substituted for plans 2lb Urethane florist foam), but eventually found the bit I had left over from the NACA.
Cut out the foam. Made a pig's ear of the 1/4", misread 6.83 as 6.33" for CS1, and didn't react when it didn't match the jig. Recut it as CS4, and buggered up the 7.94 measurement. What an asshole... Did at least notice when it didn't match the jig. Salvaged one CS1 as CS4, other is waste, but will be fine for CS6 & 7.