After I got my hand on a pair of old Japanese sliding doors with glass I decided to put these to work for my window instead of the acrylic I had planned. It would be cheaper, only the cutting tool needed to be bought, warmer, and less delicate towards the seasons temperature changes. I had never cut glass before but was thrilled to try it, and a quick how-to search on Google got me started.
The most important thing to know is that you don't get your cut by weakening the glass like in wood, but rather by the tiny wheel of the cutter putting tension/stress on the structure of the glass. The oil for the wheel plays it's part, too (my cutter had a small tank which I filled with some bicycle lubricant). Once cut, you should proceed to break the glass, otherwise the the tension ebbs and the cut "heals" itself.
Make sure that the glass lays on an even, clean surface. You might want to put a few sheets of newspaper under it to soften it a bit. When marking the cut be aware that the cut will be about 2mm away from the ruler, depending on the thickness of the cutter's head.You don't need to put much pressure on the cutter, more than that a stable and smooth motion from start till end will get you a clean cut. Than break the glass over an edge.
Here are my frame parts and the ledge after some painting. The color didn't look as I had imagined and didn't run very smoothly, probably because it was an already older bucket, but in the end everything looked nice together.
The filigree kumiko where of darker wood so I left them like that and they turned out to give the window a rather pleasant appearance, even the height looks just right. And the glass gives the window an old-fashioned look.