yes, the purer it is, the more yellow it will look. i've made 4 fina kits now, and my best mix was the most recent one.
what i did was after i mixed the fina with the BA, i heated it in a boiling pan. then, rather than adding oil to the BA/fina pellet mix, i poured it into the pure oil vial. there was a bunch of gunk in the BA/fina vial left over. you see, if you don't heat the BA/fina while you're dissolving the pellets, you won't get any binders to come out of solution. if you heat it well, then the'll coagulate, and come out of solution (sometimes you even have to heat it for a bit even after all the pellets have dissolved). that way, you get a lot of that shit out before you even filter. later, i heated the new oil/fina mix (while periodically shaking vigorously to get all the fina into solution), and got even more gunk to come out of solution upon letting it sit. i let that sit for 24 hrs so that all the particulates settled down, then reheated, then filtered, and i got a clear/yellow oil. pretty much the same color as the pure oil
one other thing, i used less BA then the kit gave. we all know BA is bad for you and causes painful injections, and i found that even with 1.5 cc's less BA, the fina still dissolved well. just make sure you bake well so that all the bacteria is killed.
-beef