Help with old overflow box’s

[Psychonaut]

Hey y’all so I’m getting ready to buy this used 120gal tank and I’m just a little at a loss about what to do about the overflow box’s.

The return is lower that I’d like, but I can just guide the locline up towards the top of the water line correct?

But the overflow boxes don’t have an outside box. And I don’t think there is enough room in the inside box to set up he piping for a bean animal.

I’m looking for recommendations about how to plumb this thing. Really I feel like it’s more drainage than I’ll need. I was considering just pulling out all the bulkheads, plugging most of them up, and adding 2 of those eschopps single bulkhead overflow boxes.

I’m just worried that because there are 3 bulkheads I’ll have a hard time finding new overflow boxes that line up perfectly to the holes already drilled

I have never done this before so I’m sure I’m missing something, I still haven’t bought the tank so if there are more questions i should ask please let me know
Thanks!

 

[Psychonaut]

Trying to get a picture up here

Or is this just an internal box and I have to work within that inch and a half or so