I would talk to Darren Hefty at Hefty Bros.  Just a dab for experimenting can be a problem because it is sold in mass quantities.  100 ton is a small order and would cover 100-200 acres.  Gypsum can be shipped anywhere by truck, barge or rail car.  If any of you are thinking of a barge full or a few rail cars full, call Joe Ploetz in Cincinnati.

Maybe you just want a ton of higher priced pellets to experiment, they are easier to handle.

http://www.flyashdirect.com/agrosoil/

Ed