We're talking about mostly 4, 6 or 8 ounce batches here but, i don't use hardner or softener. If i want a harder mix i just add hard to soft or medium & if i want it softer i just add soft to medium or hard. Doing it like this the only thing that changes is firmness because my colors, amount of glitter, highlights etc. stay exactly the same & so do the amount of plastic used in each shot. I use heat stabilizer on old remelts that i store in coffee cans. Working in small batches like i do makes it easy to tweak them any way i want & still be pretty consistent. Sometimes i'll have enough of a certain firmness of plastic that i don't have to order it & just order the medium that i use way more of anyway.