Did you ever get your glass cut? What a PITA that can be. Just a few tips as I have done this and like you have found it to be quite difficult. Oh one other thing, first thing that came to mind when I saw the picture of the glass edgewise was , man thats pretty thick, going to be a little tough to cut that with no prior experience.
Any way, use a lubricant when scoring the glass, water works ok but WD-40 is better and easy enough to clean up afterwards. Apply firm sturdy pressure on the scoring tool using a good straightedge to guide the score line line, just one pass is all it takes. You may want to practice a little to help develop your technique on some of the broken pieces you have from earlier attempts. Once scored you can either support the glass along the score line to snap it or possibly over the edge of a firm straight table. An extra hand really helps on this step as it can be difficult by yourself. Once done you can sand the edges of the glass to remove any shards leftover on the cut edge, a raw cut edge is sharper than a razor so be careful when handling.
Hope this is helpful and good luck.
Any way, use a lubricant when scoring the glass, water works ok but WD-40 is better and easy enough to clean up afterwards. Apply firm sturdy pressure on the scoring tool using a good straightedge to guide the score line line, just one pass is all it takes. You may want to practice a little to help develop your technique on some of the broken pieces you have from earlier attempts. Once scored you can either support the glass along the score line to snap it or possibly over the edge of a firm straight table. An extra hand really helps on this step as it can be difficult by yourself. Once done you can sand the edges of the glass to remove any shards leftover on the cut edge, a raw cut edge is sharper than a razor so be careful when handling.
Hope this is helpful and good luck.