you can try mixing the greenbacks with g12t75's
I wasn't a t75 fan, but they were the best match for my ex modded JMP50 (the mod was pretty similar to the Brown Eye tone, maybe more gainy)
I tried rola G12M blackbacks with 55hz cones, mesa v30's and silverbell clones, but the 75's really matched the amps voicing by taming the upper mids and adding a lot of punch
all the others sounded way too bright for that particular amp
I regret not trying to mix them with the blackbacks before selling them
I bet that combination would be perfect
those speakers have opposite voicings and close sensitivity