Redoing plumbing on 160 with corner overflows

[Sasq40]

I will be moving in a month and sticking my tank in the main living room so I need to quite down my plumbing. What's the best plumbing method. Right now I have a return and Durso in each overflow. I'm thinking it's 1 and 3/4 but will need to check. Right now I have the left going all the way to the right with 2 90s and the right one goes straight down. I'm not opposed to a new sump either. Right now it's a 55 gallon. With a bubble trap in the middle. Used to have a 20 gallon refuge but the glass cracked and it took 3 tanks to get the hole Drilled so I won't be redrilking another one

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