using a slow speed - a dremel tool is not ideal, sorry
a metal tube, and some valve grinding compound (a quite abrasive paste)

this method works well

and yes, for cutting glass any lightweight oil aids in the cutting
sound odd, but glass does cut better and easier when oil is dispensed on the cut line
something about glass being a liquid substance and the oil prevents it from rejoining as the cutter passes
yeah, i know, but it does make it easier - and makes me sound crazy