I usually use the regular tanning mousse from St Tropez and obviously with that product I will shave & exfoliate 24 hours before use. The Gradual Tanner however seems to be a substitute for daily moisturiser so do I still need to leave 24 hours between shaving & application? Or can I use it straight away? (I've looked on the St T website and it isn't clear whether the 24 hr rule applies to the gradual tan).