If u drill get a nice bit and a press.
I have a old, what I would call modular craftsman press that you put a hand held drill in. The press is mounted to 1 inch or so steel pipe so you can do whatever you want with it for hight.
Don't get the crappy bits from lowes, burned thru 4 of them doing 6 10 gal
tanks with a hose on it and low low rpm.. Just junky bits.
Also went to harbor freight (east coast) and bought a 18$ variable rpm drill so you don't wear out your fingers trying to keep the drill rpm the same.
Just what I have learned from drilling tanks, I personally wouldn't do it ever again, IMO
the energy savings of one heater vs 6-9 isn't worth the hassle of drilling and plumbing.