RE: scent free insect repellent
I like no stinking bugs for fishing and scouting but not for hunting. I use a thermacell for hunting. It's odorless and works better than any spray I've ever used. It's one drawback is cost and cost of opperation(roughly $0.50 and hour). I know $.50 an hour dosn't sound like much but it adds up over a season.
If it's breezy I don't use it because the bugs aren't bad and it dosn't work great when it's windy but on a day when the air is still you can literaly count the mosquitos you see on one hand.