im going to try to say this as kind as possible, you need to buy a good beginer cue... if your asking if fiberglass is better than wood and about weight than you shouldnt have a custom cue IMHO...
weight of a cue is on you and you only, noone can tell you what weight... you have to experiment on your own, i play light cue as others play heavy, and a majority are gonna be in the midddle...
a little advice when feeling for a weight preferrance keep a mental note of the balance point of a cue, i feel it matters more than the weight, a light cue can feel heavy shooting and vise versa...
if you dont know what all you like and shoot best with than a custom isnt for you...
good luck tho, im sure theres a line of makers here that will guide you if you want