Gino,
I'm sorry to hear of your gloss-coat experience! That's too bad, but exactly what happened to me the last time I was doing a model car on contract. I made new glass, using the wet-sanded down originals as molds. Wheew... saved that one, and learned to never do that again. That's when I learned the virtues of glossing with Future Floor Wax, thanks to Swanney.
Heller has been known, in the past, to replace parts that you write and complain about... sometimes, they replace the entire kit, but either way, if I were you, I'd write or e-mail Heller,and hear from them,before proceeding.
If none of that works, have you ever done "work bench vacuforming", using the kit pieces for the molds? Generally, I prefer this method because it makes the glass look more to scale than the thicker kit pieces; I'll be happy to make you some illustrations on the process if you want.
Take care, and good luck!
Frank