1) either.. I think it's super 77 that is more of an aerosol and drifts around, so if your arms are hairy it will feel weird after using it..
2) no
3) just spray both the wood and the carpet back, let dry until the glue doesn't come off the wood or material when you touch it (tacky but not wet, usually takes 3-5 minutes) and then apply. If you have to pull it up to readjust, you will have to spray both sides again, then wait for them to dry before putting it back down.