I`ve tried those things & all I can say is good luck getting a platform to start from. I even tried a tile saw to get a square edge for starting,
unfortunately the saw makes chips all along the cut line that are hard to get past. Look around your area & find a glass shop where they cut
glass for windows in commercial buildings. Most of that will be 1/4" to 3/8" thick and is very easy to cut with a normal glass cutter.
I hit my local glass shop & they agreed to save me a few pieces of scrap to try out, no charge since they throw "drops" in the dumpster
anyway so it`s just wasted if no one can think of a use for it. After I got used to pressure flaking from a square edge (gets a nice flake
pattern to start with) it was easy to thin & shape for points &/or blades.
If you try bottles (beer bottles work good) get large bottles to start with, like a 32 or 40 oz. The bottoms are plenty thick enough to
get your convexity & will make nice hunting points. Be sure that you have some decent safety glasses if you don`t wear glasses. Glass shards
sometimes fly where you don`t think they will & 1 in the eye will stop ya quick. Also, as has been mentioned, ventilation is a must. I use a small box
fan on low blowing across my knapping area in the basement. Mine blows from slightly behind me from right to left. The breeze should keep the silica
dust out of your lungs (I hope anyway).
After I made a few points I gave them to the employees of the glass shop & made some new friends. They even call me if they don`t hear from me
for a couple weeks to see what`s up... that`s when you gotta watch out though, they like nice sharp pointy things. Last time I was there they sent me
away with enough glass to keep me busy for a month & the stockpile grows faster than you can knap at times.