Thanks for the responses.
The style I am trying to achieve is a very slight faux hawk (not to dramatic) with just a few blonde highlights at the top. Very subtle ..not to dramatic. I do all the basic stuff myself... and whenever I get cut ins or whatever I go to Alicia's hair salon here in California.
She specifically told me that she thinks I should order the unit all blond and then she would too would use the foil stuff etc.
I figured it was easier to order the piece like a I always do(which is very dark brown) and just use a product like Mr burns mentioned at the "tips" but Alicia said that it wouldn't work.. that I need to order the unit all blond and then do all the coloring.
So James.. If I am understanding you right.. you too get the pieces all blond and then do the coloring to whatever you want?

Mr Burns? You have done the highlights of blond tips on dark hair and it worked for you?

Thanks