Which is the best speculation here? Or what would you offer as a better guess?

Question

FINDINGS

Kex III (21-30): -A1E3, -A4D6, -B6D4, -C3F5, -D5F2, --E6F3, -E6F4, +B5F6, +D4E4, +E4E4

SPECULATIONS

"Findings repeat"
"+X9X9"
"-X9X9"
"-X9Y8"
"+X9Y8"
"A's, B's, and C's are alike, i.e., +A9A8, +A9B9, +A9C9, +B9B8, +B9C9, +C9C8"
"Jack's Hypothesis: -A9D9" (ref "Kex I")
"Hayes' Guess: +B2C2"
"I will not speculate" (ref "Kex I")

Best Answer will be selected on strict criteria.

Answer 1

Clearly, it's yabba dabba doo.

Answer 2

+ and - A5A5