Drill my first hole! (Sucessfully!)

[xtreme]

I did 2 holes through 1/2" glass no problem with my mops bit. I would think you can probably get the 2 more you need with it. Silicone shouldn't be necessary for your bulkheads but I think some people use it for peace of mind. Don't use a wrench when tightening it, hand tight is all you need.