i think 0-3 gaps up to coming to 43... then u get all light and fire usefulls skills to 43 and only 1 mastery to 52. Then u delevel that mastery to 43 and farm with 9 gaps at ishades (i know is full of boters there, but u can farm really fast).
an advise?
farm only what u need to take fire and light 54 (3rd book of must piercing)... then 0 gap to 72++, only rising fire with imbue and nukes (farm at higher lvls is the best choice ^^)