I will use any glass as long as it is clear glass....or clear glass. It can be frustrating at times to build a bow with beautiful wood and see a minor streak here or there, but I quickly overlook that to see the beauty of the wood beneath.
I have never seen a perfect bow, woman (don't look at men ), deer, shotgun, dog, etc, etc. They all have their blemishes. Heck, one of my favorite critters are wart hogs. They have a face that only a mother could be tolerant of but I sure do like em.
BigJim