If you wanted to be really anally retentive about it and also slightly increase its effectivness then you could shower before each one. minoxidil is best when aplied to clean scalp and minoxidil does leave a thin film after it dries. It would be a big bother though. Some people like to apply minoxidil right after their shower while the scalp is still hydrated as this increases penetration of the minoxidil by 5% or so. That is what I do. I apply xandrox15 to towel dried hair with the scalp still slightly damp. That's what I do I apply my big gun when the scalp is fresh, clean, and hydrated. That is the prime enviroment for absorbtion. One thing though, the makers of Reten-A (retinoic acid) say that it sould not be applyed to damp skin because this signifigantly increases irritation. They say to wait at least 30 min. after washing before applying it. So you can either wash--apply xandrox 5%--wait 6-8 hours or more--wash--wait 30 min--apply xandrox 5% with retin-a or just wash--aplly xandrox and then 8 hours later aplly xandrox 5% with retin-a on top of it. I dont think that it would make a signifigant difference. Also regarding the thin film that is left on you head after each application: I would think that the makers of rogaine would have taken this into acount and chose something that can be gotten through easily. Maybe the alcohol can cut thourgh the PPG very easily. Also Dr. Lee's stuff contains much less PPG that rogaine or its generics, I I think that this would be even less of a problem for you.
With regard to how much to apply: you can see that I apply minoxidil in dangerous amounts. I would not recomend this because terrible things will happen to you. Lazyness, fatness, flatulance, impotence, and very, very, oh so very tiny genitals. Also stuff with your blood pressure.