You are leaving too much resin in the mold and you aren't holding the fabric against the mold, especially in the corners. You need to treat this as a hand lay up in which, HOLY SUCKING PLASTIC, BATMAN! you have a vacuum bag to hold those fibers against the mold after you push them against the...
Does your material have to stay on site? A shop that machines large quantities of stone or glass will have saws and/or waterjets that are designed for cutting ceramics and related materials (some "engineered stone" for countertops is nothing more than quartz bonded with filled polyester). For...