We currently sell fiberglass by the roll. Our stock varies, so please ask us what we have available at a given time. We are likely to have the basics (matte, woven roving, and cloth tape).
The resin should fully soak through the fiberglass
A mistake that can be made when using fiberglass is to not get the resin through all of the fibers. What happens then is that the surface glass gets coated in resin, yet the under layers of glass threads remain unsoaked. This will result in a weaker end product, and is to be avoided. To see a microscope picture of this mistake in practice, please see SEM_Images#3210_LVP