I do about 15 lots of foils a week, the above is back to back foiling when u are applying a hi-light or low-light and base colour all at once! so yes with bleach start with a lower % as this will be on longer, then u can up it to a 9% if u need to near the front and sides! small neat sections about half a cm weave through, under weave base colour, get it right on the root, then bring the top weave over keeping your tension good! Get the foil right to the root using the pin tail apply half an inch away from root to start, then nudge the colour up a few mm away from root, you dont want too much col/bleach up there to avoid bleeding!! fold your foil neatly, tuck sides in and carry on. When finshed with foils if only parting or half head, pin them up and out on the way and apply base col to roots as normal elsewhere!:hug: