The Gamma Scout is an alpha-beta-gamma meter but it uses an LND 712 end window Geiger tube with a system of shields to distinguish between the different radiations. It's an interesting consumer-market focused product and is too insensitive to do you much good. It's not a serious instrument for use in health physics applications and the readings can be misleading to the point of dangerous. I actually corresponded with the inventor in Germany a year or so back when I was writing reviews on radiation survey instruments for another internet board. It's an interesting idea but not useful in your situation.
The problem with looking at large quantities of anything is that the dangers within are unknown and not easily detected on a macro basis. I like sensitive gamma scintillators just to get a sense of the gamma radioactivity of unknown bulk material. That said, this can also be misleading in that the presence of radioactivity can be of naturally occurring isotopes in the material (my office at home is about three times background due to the granite facing stones on my house). The opposite is equally true in that the absence of a reading on a gamma scintillator doesn't mean that it's not contaminated with alpha or beta emitting isotopes.
All this said, best advice is to work with a professional health physicist on the appropriate method. I sure want you to be working with the professional advice from somebody closer to your situation. Good luck.
Bill