Overflow design question

[Palytoxinhallucinations]

So I am getting a tank built 24x22x20 with a 24x14x15 (inches) sump, and a return pump that will move about 300 gph (after losses) through the system. Getting 3 holes drilled in the center in the bottom of the tank because I don't want any plumbing outside the tank/stand. So I was thinking 1" bulkheads and pipe for the main drain (with gate valve) and EM drain, and 3/4" bulkhead and pvc pipe for the return. I wouldn't mind making the drains a bit bigger but would like the internal overflow box to be as small as possible. I'm pretty sure the 1" drains can handle the flow I'll have but I've been running sumpless for years so what do I know. Can anyone think of a reason I might later slap myself for using 1" ?