Get at least 1 Spears gate valve for your main drain, they are pricy but it’s what you want. For flow on your returns and other valves I like hydroseal ball valves.This is the overflow I’m getting.
https://www.fijicube.com/products/low-profile-external-overflow-box-1200pgh?variant=13517735002181
I do plan on having a valve.

