LOL. Thanks for the answers. I know the hole size is what ultimately matters, but since it's threaded and the pane on the tank is 3/4" - I'm worried there won't be enough threads left to attach the rest of the plumbing to connect to my filter. The tank is still being built and the thickness is already pre-determined (and cannot be thinner than that) at 3/4" thick to prevent bowing. The tank is a 90G, not your usual Monster Fish Keeper by any standards.
wow 3/4" on a 90 gallon? impressive, but maybe overkill. the bulkhead should be fine lookin at the thickness. but like everyone said, the important part is the width of the hole and bulkead. geez 13.99 for that? usually at the lfs theyre around 5-8 bucks.