I have a sturdy sideboard that is 46" long - does anyone reckon a 1" overhang each end is OK, or probably best to fabricate a top the size of the tank?
Welcome Lurch
As above I would definately not chance it, I vaguely remember being told once its the edges of the tank that actually need supporting than anywhere else.
You can buy tanks with floating bases but not floating edges ( Well except very small tanks )
I've got mine that overhangs but only by a few mm i wouldn't recommend it either, it may not give way because of the weight but over time i think the tank may start to bend or bow and seals may give way
Cut some 1" thick plywood to the size of the bottom of the tank, a hair bigger won't hurt. The plywood will easily support the 1" overhang on each side.