I use my DeWalt cordless drill and never had a problem. I've drilled a dozen or so holes. Go slow rpm, don't put weight into the drill (just use the drill's weight), use water to cool everything, and make a plywood or 1"x2" guide. I've got to drill another 10 gallon tank. I was planning on taking a video of it so others can see how I do it. Maybe I'll do that Sunday.
I won't be available this weekend, but if it can wait until next weekend, I should be around. It will take us between 5 and 10 minutes per hole. I live in Irondequoit, just off of 590. If you want to meet up next weekend, let me know.
I'm sure you can guess why the flag is upside down... Still mad....