Had two 8" plus brace height bows in recent years that shot horribly for me (or I for them ).
Yep, definitely you.
And I guess also that means that any power gained comes not from any brace height, real or perceived -- or "effective" as we've been calling it in this thread -- but from the powerstroke of a bow as you've pointed out.
Actually, brace height is half of what determines the bow's powerstroke. The other half being your draw length.