Hair Color Level

I was searching the net trying to learn as much as I could about hair color and one thing that is tripping me up is my Level. A while back I higlighted, colored, stripped, colored, stripped my hair. (its fine, I havn't done anything in about 5 months) I think I have normal porosity and I do realize that when I tried to recolor to get back to my natural color my stripped hair took the color like crazy which is why I ended up with super dark hair after using a level 5 color. I have several questions, first is how long after stripping does it continue taking color super good. Second question, I was trying to determine my level using the swatches at sally's and my new growth looks like a level 5-6 which is considered a dark blond, I never thought of myself as a blond I always considered myself to have medium brown hair. Whats up with that? Third question, if I have alot of red in my hair would I use an Ash or a blue toned color to cancel it out.