Just pulled my Tron apart this weekend so...
A = 1 11/16"
B = 1 5/16"
C = 20 7/8"
D = 2 11/16" (to the near edge, not center)
E = 2 3/4" (same)
F = 1/2" (same)
I don't think it would really matter if C was 21" or A was 1 3/4". The only measurements that seem to require some precision are D-F.