I currently have a Visio 80ish gallon RR tank. It has 2 holes drilled in the overflow. One is 1.5 in. and the other is 3/4 in. I used the 1.5 for the drain and the 3/4 for the return. The 1.5 was Tee'd off to two 1 in. into my sump. I am debating going to the herbie system and drilling the back of my tank on both sides with 1/2 in lines. Anyone have the same type setup? Anyone do this before? Any ideas on how to go about it? I plan on going through glass-holes for the drill bit and plumbing parts. Has anyone used them?