Sales & Royalties

I am wondering this: What can I ask for in a sale of mineral rights., such as bonus money or retention of % of Royalt. . We are 50/% owners of 160 continuous acres in Logan County, CO It is the largest bloc -ownership in the 1/4 Section. It is is not producing yet. I have been told it could be worth around $200 per acre, but no discussion about bonus money or any royalty retention. I am doing research, but can’t find much. Thanks, Wes Tucker