RE: smoke as a cover scent?
No. Not in my opinion anyway. I seem to be winded more than ever before when I get careless and sit in my hunting clothes next to the camp fire. Cigarette smoke can help them wind you as well. I know some people hunt with both odors and are successful, very successful,such as GregH smoking on stand.
I dont subscribe to cover scents, I just try for scent free as possible.