Need help deciding dimensions of external overflow

[HighChiefKC]

Been out of the hobby too long and I’m overwhelmed with how much has changed. Looking at custom 225g acrylic 72x30x24 and doing a coast to coast external beananimal overflow. Builder asked me what dimensions I want the external overflow to be? Well I have no idea! Any recommendations? I’ve never done external or beananimal so this is all new to me.
I just know I need it to fit through a 36” door to get to the basement.
Thanks!

 

[Reefing Madness]

 

[NeedMoreReef]

60x4.5x8 would be nice.
that's a great size tank. my frag tank is peninsula 48x33x12 and has an external overflow that is 20x4x8 and works well. fits 1" bulkheads.