I don't believe in cover scents but I do believe in being scent minded i.e not pumping gas. I am very mindful of the wind.
I am big a big fan of a drippers and tinks when the time is right. I stay covered up w/gloves, wear rubber boots and try not to touch anything.
My theory is that your smell that a deer smells is not vapor but particulates, (unless you spill gas or something else that has a vapor smell) in short your dead skin that is constantly being shed, sorta like dust. Drug sniffing dogs work this way...
I agree with everyone about the wind. I'm not a big believer of the scent block stuff. Do I use them? Of course. I spray down before I go into the woods, keep my clothes in a seperate closet with earth scented wafers on them, wear rubber boots, wear scent blocker clothing, blah, blah, blah, the whole 9 yards.
Keep the wind in your face and you'll be fine. I've gone into the woods plenty of times hungover or after a night of drinking and I'm sure I smell like I actually jumped in and swam in the liquor bottle but I still see deer.
When it comes to putting out the doe estrous or other scent attractants, put it out earlier that day or the day before.
Good luck and keep at it. You can't expect to see deer everytime you hunt.