I recommend you call Eldon Hampton, owner, Geothermal Distribution, Rockwall (near Dallas), TX, at 972-679-1438. Geothermal Distribution is a WaterFurnace GeoPro Master Dealer, and has been very successful installing GSHPs in our Texas clay soils for over 10 years. In addition to regular size residential settings, a good portion of Geothermal Distribution's business is very large residential and commercial installations (particularly large school complexes).
I realize Texas isn't New Jersey, but I'm aware that Eldon travels occasionally to manage larger projects. Hence the recommendation here.
Feel free to state that the recommendation to call came from me if you wish.
Good luck!
Best regards,
Bill
Dallas (Plano), TX