I have used skin so soft with little effect.. (apart from making me look like a greased up body builder) I find bog myrtle is the best solution.. Camp in amongst it, and no midges, or boil some up and leve the water in the porch. Rub it on your skin and they dont bite, and walk about with a sprig behind both ears - sorted
Doesn't work in the cairngorms though, no bog myrtle to be had anywhere
Deet is pretty darn good, but it wont just ruin clothing, but also melt your tent, so always apply outside