Just drilled the 100g! Did not break or crack it!!!!! yea.
I plan to install a "Calfo style overflow" plumbed with 1.5 inch pvc so i have plenty of capacity. I plan to run a rio 2500 for return at about 600 gph. with the 1.5 inch plumbing i will be able to run more if i want through my 4 foot long sump in stand. More later in week as progress continues. Thank everyone here on Captive Reefing for your help my 55 gal is doing well also.

PS I got drill guide at Harbor freight for under $20 it is a discontinued item. I had to dremmel the side to fit 60mm / 2 3/8" hole saw.