two kinds of glass that can be had , H and S. H is the standard everyday stuff that 90% of all kits are mode from. S glass is used to be a mil spec only material wich is much closer in property to Kevlar then H glass, cost is @ 20X that of H glass though... what will really make the difference is the resin you use WITH the matrix ( glass) polyester is the weakest , it does not take heat and tends to crack very easily, it shrinks @ 15% when cured so reach pc heeds to be done in a mold or on the vehicle in this case. Vinylester is better, it's more money but offers you less shrikage better shock absorbsion and a harder overall composite.. Epoxy is the best, it shrinks @ 3% when cured, can be heat cured to stand up to 300 degrees( standard low temp epoxy ) and is almost bullet proof when used with 'technical fibers' like CF and kevlar, ( it's also the only resin that truly works with CF in terms of bonding with it).. the price is @ 10x that of polyester and @ 7x that of vinyl.
use H glass with Vinylester if you plan to do this as a hood and any other place that gets impacts from debris.