My friends for whom I’m making this window agreed to the minor change to the bottom center border edge, so today I implemented that, plus made a bit more progress overall. I had to spend some time cleaning out my grinder (it had been waaaay too long) and changing out the grinder bit, as well.
I’m actually starting to run low on the medium gray glass. I went by Blue Heron this week and talked with the owner a bit and he thinks it is Steel Blue / White from Spectrum glass. He promised to order some for me when he places his next glass order.