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

Question

FINDINGS

Kex II (11-20): -B2B6, -C6E4, -D1D4, -D3E1, -E3F2, --E4E5, +A4C4, +B4D4, +B5E6, +D6F6

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

Oh, pretty,,, Is it a pyramid?

Answer 2

I will not speculate.