Arizona77, Niacin in various active forms, has been shown to be effective in raising HDL and in some cases lowering TC. The documentation supporting this is very sound although the claims for lowering TC are less common.
The side effects for Niacin include flushing, headaches, increased glucose, increased uric acid, stomach upsets. The flushing is annoying but generally not serious. I don't know what to say about the glucose, uric acid (gout and kidney stones) and stomach issues since they might lead to more serious problems.
I take moderate dose , about 100 mg, included with daily vitamins without problems. I don't need more since my HDL is 60 to 70 range without it. In your case, I'd be ambivalent and probably shoot for 250mg to 500 mg with RYR and see the response.Less chance of side effects at these doses. If I remember right, Lenin good good results at 500 mg.
Good luck either way