I probably make more stock than anyone I know. We butcher our own animals so I have a huge amount of bones at any given time. Almost every week I have at least 3 full stock pots (30-60 quart pots, depending on the size of the bones) of stock going.
I always simmer for a few hours (completely cover bones in water and don't forget your whey or vinegar), skimming the junk off the top, and then remove bones and clean off the meat for later use. Then put the bones back into the pot and let simmer the rest of the day. Then I'll put the pot on the back porch if it's cold enough out or let it cool and put in the extra fridge. Next morning I skim the fat off the stock and strain it. Then back onto the stove it goes (unless it's not gelled, in which case I'd keep the bones in after getting the fat off and then simmer another 12 hrs or so) to simmer down to a couple of inches in the pot. Then I either can that or pour it into ice cube trays and freeze. Pop into a bag later. If you skim it well, and don't boil, but simmer, your stock should be clear.
HTH! FTR, I do chicken, guinea, feral pig, beef, goat, duck, lamb, and domestic rabbi stocks. And deer if I get the chance!