I can see how the number of searchers would have a direct impact on the start up costs. Number of shares purchased might be a very good way to offer territorial protection. I think this would work best if applied against the population base vs  a per county formula.

Looking at the Texas county statistics I can see where Dallas County would have much greater value with it's 3,400,578  population than Borden County with a total  population of 729.
 
If stock were issued at $1.00 per share, territory could be based on a ratio of  1 share = 1000 population base. Dallas County would then have a territorial value of 3400 shares while little Borden County would have a share value of only one share with change left over.

If no one researcher wanted to make a $3400 investment in Dallas County then they might purchase stock equal to whatever investment they cared to make. As other researchers came on board they could be given assignments in a ration consistent with their investment until the 3400 vesting shares were reached for Dallas County. I think it would be likely that all those vested in the Dallas territory would see a return on their investment. As for those of us who might want rights to Borden County assignments we might never get back the72 cent investment.

Just some thoughts