I weigh and record the parts all the time for my own reference. I hunt in SW MT. Mature bull elk are about like this with hide off:
rear quarters: 65lbs
front quarters: 35 lbs
meat from frame: 80 lbs
skull: 25 lbs
These are skin off and hock off. Add about 10 lbs per quarter for skin (if my quarter has skin on it has extra to wrap around and protect the meat, so this figure might be high for you). I haven't witnessed much variation in weight of quarters in 6 pt bulls. The loose meat from the frame varies the most. Sometimes I lose a lot due to blood shot. This amount varies the most also for bigger/smaller animals, as some have a couple of inches of meat around the ribs and some are pretty lean. Often I de-bone one front it seems due to bullet damage, too. The skull obviously varies a lot as well but this figure is for a ~300" bull with skin/lower jaw removed (5 pt skull weighed 18 lbs for reference, 320" just under 30lbs). When you shoot a decent bull you should plan to hike out about 300 lbs if you keep the bone in the quarters, and I don't want to hike out de-boned meat for purposes of hanging/aging/identifying cuts.
I hope that helps.
