I forgot if you have a center-brace in front? Unless you knock that out (while providing aux. bracing since the tank is full already), it'll be tough to angle a bigger sump into one opening. If I try to fit a good size sump under my 60g, I'm gonna put a temp-brace to the left of center, then cut out the center brace. Once sump is in place, shim and re-install the center, then remove the temp. YMMV...
Or maybe I'm overthinking this, hahaa...