my futures fins...

i just got a eps quad fish from my local guy, and the inside futures fins don’t fit. would it be better to mill out the bottoms to make them fit, or should i try for some smaller fins?

By inside I assume you mean the rears.
Might help to know exactly what’s not fitting.

You are aware that Futures have two diff depth boxes, 3/4" and 1/2".

You need the correct fin for the box depth.