enlarging drain holes?

So I got a 2" hole saw from brs and found out I didnt have the room to add a third hole. I ended up cutting a new 2" hole around the 1" in the middle of my overflow and it worked like a charm. Cutting a hole in glass was much easier than I would have ever imagined but I have to say I was waiting for it to shatter even though the manufacture told me it wasnt tempered.

 

damn, i was about to suggest this in combo with dia. grit hole saws.
"Oops" Arbor - Lee Valley Tools
called an oops arbor, uses 2 hole saws, the middle fits in the original hole and stabilizes the larger dia. saw that cuts a bigger hole with the same centre point. it works great in wood, havent tried it yet in glass, but the principle is identical, so it should work. and when cutting glass - try to do it submerged, all of the dust will be contained and the glass will stay cool, which will reduce cracking

 

Now I have a new situation with this 2" drain though. I really dont think Ill be able to fit a 2" durso in that space width wise. Any suggestions? What other styles of drains are out there that arent loud but might not be built from 2 90deg bends?

 

Just get a 2" bulkhead that isn't threaded and put in a slip reducer to 1.5".