@jacksonoil welcome to the forum! There are many contributing factors when it comes to oil and gas leases and a lot of that language may seem foreign at first glance. Before you sign anything, I believe that it is good practice to really read it over, set it down for a little while, then reread it to fully understand what they are trying to convey.
Within West Virginia a single parcel can be owned by one or MANY individuals and since you mention having to track down heirs, there is a chance that there are other family’s with interests in that land also. These interests can vary in size based on how they were conveyed previously. For example, if your grandfather left 2/3’s of his estate to his son, and 1/3 to his daughter, then their children respectively would have different amounts regardless of them being on the same level of the family hierarchy. I hope that makes sense.
As for the actual production, it sounds like 6 years ago a land company was attempting to get permission from 75% of your parcel, but when drilling is going to occur they are doing this over much more than a single plot of land and they also need consent from those owners as well. This process takes a lot of time but after they have permission, they need permits, plus the actual time it takes to drill a well and sell the gas could result in many years between first contact and first payment as you have seen.
There are a few operators in West Virginia that stipulate a low end of what they will issue a check for. For example, if you are owed $10 they may hold those funds until it reaches a threshold where they will issue a check. Without knowing your specific interest percentage or having your exact net mineral acres it is hard to say what a reasonable royalty would look like for that area. You may have 1 acre or 0.0001 acre.
Your contact most likely represents a single entity and they are often hyper-focused on areas in development. Perhaps your contact can refer you on to other companies working in your area or provide you with more details about how much land you own individually.