If you're so concerned with loss of material just use a very thin Blade on the table saw, wood and alu discs are bet. 2-3.5mm thick, however there are special discs with thickness from 0.5-1.5mm. Foam doesn't need lots of torque to be cut unlike Al or wood, it doesn't squeeze the disc like wood does, you can also make a jig and cut it with a utility knife, that is what 0.3mm ?

regards