I am another who has not had any burnt taste issues with the MaxxFusion cartomizers, even with the original blanks. And I use juice with various combinations of pg/vg, up to 40pg/60vg. Im a bit baffled by the issue; since others have reported using high vg juice without problems it doesn't seem the vg issue is a consistent variable.
So, FWIW, here is what I do that has led to my good experience with the MF cartos. Im not a heavy hitter; I take long, slow, light drags. I have only used them on MaxxFusion batteries, MF passthru, or the Trifecta. I do not use the condom fill method; I just take the rubber cap off the carto, leave the condom cover on the battery end, tilt the carto and drip juice into it until the filling doesnt absorb the juice anymore. If the juice has pooled on the top of the filler, I absorb the excess with a Kleenex.
I dont use the Taryn spin or blow through the carto to get any excess out. I dont go by number of drops, because different dropper bottles deliver different size drops. I wait for at least 10 minutes after filling a cartomizer before I vape it. I always check the battery end of the carto for any juice and dab any off before I put it on the battery. I frequently top off my cartos (while off the battery of course), never letting them get close to dry.