Matt, you have have to have a lot of patience when doing this, i would use wet n dry to take off the yellow, you just have to take it down slowly and not go through the original paint. Touching it in again is a patience thing, i build the paint up in layers, letting it dry each time and then flatten it off with a wet n dry,(again,be careful not to rub it down too much) then bring it up with t cut and it should blend in spot on. Think i told you before to get Domestic white colour as it matches the original paint pretty much perfect.