You don't rely on resin soaked fleece for strength. You rely on fiberglass for strength. You rely on your base layer only to give you a base shape on which to fiberglass. You don't rely on 1 layer of fleece to withstand the pressure of a sealed subwoofer box, do you?
Hell take a quess at what fabric was used by the alpines demo car? You know people certified in composite fabrication did it, so I'm sure they used the right material right?
Yup you guessed it.
poly cotton blend fabric aka spandex
Hell look at the curves I got with my dash and prove to me you'd be able to get that same detail using some of your average wal mart fleece that absorbs a whole can of resin and ends up giving you a false impression of strength.
Hell, I'll let the pictures speak for themselves.
Figure it out yet? You want something that absorbs as little resin as possible while giving you a strong enough base to lay fiberglass on. Spandex does that perfectly, and allows you to conform to incredibly tight curves, as well as allowing you to use fiberglass to build strength. NOT RESIN.
You'll learn sooner or later though...