New GPS setup

We grow trees in a row crop situation and need the GPS to be as accurate as possible and the rtk I have bought is suppose to be 10mm horizontal and 15mm vertical but we will see.
I want to know what is my best option for a GPS in the tractor none of my tractors have a hydraulic steering valve so I will need electric and none of the local dealers will unlock a GPS without payment for the claas S10 that is $6000 same for trimble.
I bought the RTK because I refuse to the signal correction cost on free satellite signals of $2000/year or cellphone at $1600. .

Both the trimble and S10 have good data entry and save ability which is important for us as our work is all about saving and recording information now days.

Does anyone know how to unlock either of these systems or have a good solution as an alternative. Even a comparable unit that does a similar job in another brand?