Are you fairly close to the Silverbrook cemetery in Anderson South Carolina? If you are close enough to the grove, I've heard that they do allow people to dig moso divisions form the perimeter of the grove.

My suggestion is to dig the smaller culms on the perimeter because they tend to have more exposure to the sun, more overall stored energy, and establish a lot faster.

I would suggest going for a visit and then digging out some massive multi-culm divisions 200+lbs. I would suggest going before April because that's when shooting season happens. Divisions won't be nearly as successful or energized after shoots emerge.

Here is a link that might be useful: forum link to location

If the above advise is not an option, I would look at red margin (Phyllostachys rubromarginata) bamboo. I have read studies from research that this variety is the fastest to spread and fill in.