.5mm vs 1mm Oversize Pistons

[DieselScout]

My D24 NA engine block is currently at the machine shop.
They said that I could probably get away with using the old pistons with new rings if I really wanted to (Not inclined to do so) as the cylinders aren't super worn.

My initial thought is to only step up to a .5mm piston (to enable future cylinder work if it wears down again), but is it worth considering a 1mm piston for the extra power/fuel economy?