When I smoke, I let the smoke go straight to my lungs. Usually. I'll take the biggest hit I can, inhale deep, let it settle, and blow out. Sometimes I'll do a little french inhale or smoke rings, etc. But otherwise, yeah, lungs.

I don't believe your weight should have any impact on the amount of weed you should or should not use. Smoke goes to lungs...to your bloodstream...to your brain...no mention of fat. Doubt it. I know plenty of overweight smokers and plenty of skin and bone smokers. I notice no difference in amount of intake. Errrbody just gets high.