Leasing mineral interests under a proposed Solar Farm

A solar energy firm wants to lease our minerals in Garvin Co. OK T&R 4N-2E (parts of 6 sections). The company has offered each family member a flat sum to lease our minerals in their target area for 40-50 years. Family members have a total of 1100 net mineral acres (nma). OCC Well Data says there have been 53 wells in the T&R with 51 PA. With these results, I feel comfortable leasing for a long term. Horizontal wells to reach any minerals we might have are okay. My question is how much we can charge for our nma on a per net mineral acre basis?

Thanks,

rx777