I've posted up a few explanations on how to use drywall tape (nylon mesh) as a matrix for tough fiberglass. I oughta post up a tutorial on it. I'll do it the next time I make a helmet as I have to remake my MKVI helm anyway. The Ultra Thin drywall tape works excellently if you get at least 1 layer down and then add 1-2 more layers on the areas that you need extra reinforcement. I have normal drywall tape that I haven't used yet as it's a way coarser mesh but I think it'll definitely work with a minimum of 2 layers. If you do use this method then make sure you're using a bristle brush and not a foam sponge brush as you want the resin to fill up the mesh instead of just glossing right over it.
Basically it's just a way to thicken up the fiberglass enough that you have a resin shell on the inside of your armor.
PM me if you have any questions.