Two doors are fine. Just be sure you have settled on your filtration methods now and size the openings appropriately. Many of the larger canisters are a hassle in standard size cabinet work to get them in and out, and to even route the thicker(larger) tubing from them out and back up to the tank top. Same for a sump..leave more than adequate room to work on it and to remove or replace it. More than adequate for me is 6" more than I think is necessary, lol.