Washing Your Weave and Holding Your Style

Hi im glad i found this forum!!!! i have a couple of problems with my 18" european style natural hand braided weave.
I can see build up from gel and holding spritzs on the areas of my scalp that are hard to reach (around the braided bits and between the tracks) what is the best shampoo to use on my whole head and how often should i wash my whole head - i wash the top of my scalp where i have a bit of my own hair to cover the parting every week but to do the whole head takes like 90 mintues cuz it takes so long to dry and straighten.
Also my own hair is fine and flyaway and the small amount i do have to cover the parting keeps blowing up in the wind and revealing the top track!! it just wont stick down to the hair unless i use a whole load of holding spritz (lux) which makes my hair hard and it flakes when it comes out - any other products that would be good at hold my style and any other help would be greatly appreciated to make the most out of my weave thanks!!!