It depends on if you are dry-curing, or wet-curing. Remember, the nitrites in the curing salt (Tender Quick) are doing just that;
curing. I don't know that I would attempt to dry-cure a brisket. I don't think the flavor profile would be what you are looking for, and the potential for over-curing is great. I would go with a brine, like this one:
http://smokinitforums.com/index.php?topic=1235.0
You could modify the ingredients, based on taste, but use the #1 curing salt to get your ring. There is a difference between #1 curing salt and Tender Quick. The tender quick actually has a lower amount of nitrites/nitrates than the pink curing salt, and is intended for dry-cures. #1 cure is intended for wet (brine) cures.
You're right about not playing around with cures. Do some research on the site, under brines, and educate yourself. Walt has a good brisket brine, and you could just add 1 tsp. of #1 cure to it. I know this is really just for academic purposes, since I don't worry about a smoke ring at all, but I'm glad to help in the "name of science!"
One thing to remember is that you will not get good nitrate penetration under the fat cap, just on the flat side. This may be a case where the juice just isn't worth the squeeze.