3-4 inches is plenty high enough. Teff will need heat and some water to get regrowth.

Drying teff is easy, get it out of the windrows.  If you've got a hay fluffer, turn the teeth and blow the teff out as wide as you can. I throw 2 rows toward each other so it looks like one really wide (but very thin) windrow. IF you have dew that lasts till 1100 the daily drying window is very small.  Crimping again won't help that much, takes sun (heat) and some breeze to get the teff to dry.

Right temp and wind conditions provided windrows are wide as possible, might dry down in 3-4 days.  Once the Teff is dry (don't bale wet and think it'll dry in the bale, it will not) get right in front of the baler with a twin rake and put the rows together. Do NOT get ahead of the baler, only windrow what can be baled in the afternoon (or one day) 

Teff is like a sponge with water, put too much into a windrow ahead of the baler and it'll be as wet the next morning as if it was just cut.

Teff will have to be baled tighter than say alfalfa,, there is nothing to hold the teff together like alfalfa or the other grasses. Too light a bale and the strings will slip right off the bale.  Soon as the teff is baled get it off the field into a stack. Teff will soak up water over night left in the field.  Preferably store teff inside, if outside get it off the ground and cover well with a tarp. Teff bales will absorb water very easy and quick.