DIY Overflow pipe

I am currently building my stand and canopy for my 90 gallon tank. I am going to do an DIY overflow like I have on my 55 Gallon tank. On my 55 Gallon I have one on the back at both ends. On my 90 I have going to have two of them at one end, one lower than the other. I am just currius as to what you all think I should do for the size? 1" or 1.5" or 2" The return pump is a Mag18 i think or very close to that. The tank is going to stick out from the wall so that both long sides can be viewed.



My 55 Gallon is about a week from being 1 year old and is doing really well. I am going to transfer everything from the 55 to the 90.



Any advise or thoughts would be awesome.