When in doubt start towards the higher end of your rental-payment spectrum and lower your price accordingly or for a certain renter.

There is no guru book  or course that teaches the real estate spectrum necessary for land speculation, you better begin by learning the fundamentals of real estate and master the basics before trying to  deal in the raw land market!  

By establishing this relationship on a "mutual respect" basis understanding that Realtors®, like Wholesalers and Investors have their place in the real estate spectrum you will undoubtedly find that your results will be far better!