Just came across this thread. You probably have your answer by now but if not here is my opinion. At 6 feet your male Dumerils probably won't get much bigger. I did see one at a swap once that was an absolute monster at about 8 foot and about 6-7 inches in diameter but that was a rare exception I tink. I have one now that is about 5 foot and I've had him for about 6 years and I've had a couple of others over the years and none were over 6 feet. They are my favorite "large" constrictor and by far the most docile I have ever worked with.
I seem to recall a quote by Bill Love (he does Madagascar ecotours) saying he had never seen a Dumerils over 6 foot in the wild so they don't get very large.