George
If you want to take 310.15(A)2 into this problem I well need distances.(10% or more of run in Hotter area??)
310.16 correction factors, Tables 310.13
125 F -#2thhn = 130 X.76= 98.8
80 F -#3 thw = 110 x 1.00 = 110
240.3 up to 800Amps next highest breaker .
240.6 98.8 next higest 100 amps.
100amp breaker should be fine .
Unless distances are great I;d just run #2 total run.
I think I understand what your after???