Current bonus/royalty lease terms in Bienville Parish, LA

I am a partial owner of 340 acres (I have a 1/8 undivided interest) in Northwest Louisiana, specifically Bienville Parish. We have been approached by Covey Park to drill on 70 acres. They have offered us $1500 per acre bonus, and 25% royalty. There are other wells on our land that are producing natural gas for which we receive royalties (only 12.5% before deductions from well operator). I wanted to know if anyone else has signed any leases recently so that we can have a better idea as to the going rate. If so what were the terms of the lease? How can you get the royalty agreed upon without having them deduct for additional costs? Also, what is the time period of the lease in years. Covey offered Three years in paragraph 2 of the lease.

Any help would be much appreciated.

The location is SECTION 25, TOWNSHIP 16 NORTH, RANGE 10 WEST in Bienviille Parish.