I was nervous about drilling my 40b that cost me $40... so I can totally understand. It's really not that bad actually. Just be sure where you want it, because it's hard to move the hole once it's drilled. I drilled mine slightly lower than I should have, which has annoyed me ever since. Make sure you account for the flow. If you're going to have quite a bit less than the max flow, move it slightly higher than you would if you are going to run it closer to max flow. Mine is 700gph. At about 550-600gph, It ran about half way up the teeth. Now that I'm closer to 400gph, it barely raises above the bottom of the teeth, making my water line slightly below the trim (annoying!). I used the plywood guide that came with it as a drilling template. I set my drill on the lowest clutch setting and had my wife eyeball it for level both directions. I just pulled the trigger (pun intended) and kept at it applying no pressure. About halfway through I added a bit more water and kept drilling. Just make sure, as the instructions say, to have a blanket or something under it to catch the glass chunk.
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