Mid grade weed is just that: Mid grade.

It doesn't refer to sativa or indica, just the quality of the weed.

The two types effect the high you get off of them. Sativas give more of a head high, more giggly, more energetic, while indicas give more of a body stoned feeling, more relaxed and narcotic.

Any type of weed can be made into hash, but often indicas are used because they usually yeild more and often have more THC percentage in them. But i think most smokers will tell you if they had to choose between good sativa or indica, they'd choose the sativa.

Most mid-grade or common stuff you get is more indica than sativa i would guess, it flowers faster so people who grow for profit will usually grow indica or indica/sativa hybrids.

Hope that helps