Upgrading a 220G used Plywood Tank

[takagari]

I've gotten a large used ply tank.
I've check it and it holds water, but has no overflows built into it.

I would like to keep rays in this eventually. but I'm trying to figure out my drains/returns.

I would LIKE to mount a few of these on the back,
https://www.amazon.ca/Lifegard-Aqua...4435&sr=8-2&keywords=aquarium+bulkhead+2-inch
lower down, maybe two. and one at the top with an elbow to use as a surface skimmer.
2 inch may be to much, I'm worried about a ray getting comfy over them so would like any 1 to be able to handle the flow. Or is this over kill?
I was thinking of plumbing them all through the back, up to an elbow set at where I want the water level, then off to the sump.

So my question, 3 2" drains, one an elbow skimming the top, two placed lower to suck from near the bottom and middle.
If they all came together on a single 2" return on the back tot he sump. would it work?
I'll attach a crap drawing.
Looking for 1000GPH turn over also btw.

Tank pic for good measure

 

[Protek]

How old is the tank and what condition was it in? I'm new to plywood tanks and trying to get a feel for how long of a life they have and how reliable they are.

 

[takagari]

I'm the third owner and it sat in a garage for a year
I filled it outside twice to ensure I was good then inside

Seems to hold perfectly fine.

I'm trying to find a solid flooring to lay down that looks good.