RE: Cover scent or scent free?
I'm a scent control freak. I do everything I can do--outside of getting one of the expensive suits--to be as scent-free as possible.
I shower with scent-free soap before each hunt, wash everything that goes out with me in scent-free detergent and baking soda, spray on scent elimination sprays, play the wind . . . the whole 9 yards.
I stopped using fox urine and other cover scents years ago. IMO, it's like having a cigarette stuck in the middle of a pizza--the pizza will not cover the scent and you'll still be able to smell the cigarette. I stopped using estrous urines too and it hasn't hurt my success.