I don't think those are the right endmills for glass. Diamond-coated carbide tools take a much more aggressive cut, and are meant for relatively soft but abrasive materials like graphite, where the material quickly dulls a normal endmill. For glass, you want an abrasive tool. You can get diamond-plated cylinders ( a rod coated with diamond particles) inexpensively, or for more money, get sintered diamond tools that last a lot longer. But if you're just doing a few of these, the cheap ones might work. They usually come a little fatter, but you can probably find 1/32" diameter if you look around. Here's a place to start:
Diamond Carving Points - Kingsley North Use them with plenty of water.