Hey Goldie, the spoon and thinner is for making the nice smooth radius fillet in any filler ( PL or PB) the problem with PL, is that it out gasses as it cures creating the bubbles. The spoon and thinner will not help that. That is the reason a lot of folks just use PB for fillets and bedding.
Also, if I may, I suggest you look at friscoboaters threads, there in a bunch of commentary on use of PL. If I remember right, he used it on the searay build, and completely abandoned it on the glastron..... or maybe the other way...