Really, I've seen it done and talked to folks who do. They were in an LFS
working on tanks. I'd see if there is a shop near you that can do it for you.
When I saw it done, it was explained to me that the drill needs to do the work, and that if you push, you're likely to break the glass. Glass, right?
Good tools and a drill bit probably ain't something you have sitting around the house I'll bet. I've also heard stuff about glass being tempered or not and that having a lot to do with whether you can drill it. I'll bet a 29's bottom would be a huge problem for you or an LFS
-they probably won't touch it either.
Sounds like it's time to upgrade to a reef ready, drilled tank.