To break after scoring, I use a ruler placed under the sheet parallel to
the cut. Pressure on either edge (using protection if one side is very
short) usually (!) produces a clean cut. Tile nibblers will work for
any small excrescences but you need to take tiny bites.
I found that after scoring I can just pick up the glass on either side of the cut, held between thumb and forefinger of each hand, and it just falls apart with the slightest pressure. If the score was good it'll break perfectly. I had one piece of glass where my ruler moved by 2mm near the end of the cut, and the break followed the curve precisely. That's why I cut the glass a couple of mm smaller than the frame :)
I haven't tried breaking off small pieces though. For that I might follow a method similar to yours.
I forgot to mention that prior to cutting I clean the glass on the side I'll be scoring. One of the guides I read said that before scoring, the area where you're scoring needs to be free of grease/oils (ie fingerprints). I used isopropyl alcohol for this, because that's what I had available. Not sure how accurate that info is though, considering that you're supposed to oil the glass cutter blade.
Cheers,
- Dave
http://www.digistar.com/~dmann/
