I hear ya Bob. It makes no sense to me for the average 60-70 year (that's our mean average age) old, traditional muzzleloading shooter to beat themselves up toting a HC Hawken percussion rifle weighing in at an average of 11 pounds. Nor, to subject themselves to the pain of a 1.375" wide × 4" tall, deeply curved, HC Hawken buttplate.
At 67, with osteoarthritis well established in both shoulders, if I was going to have a hunting rifle built, it WOULD HAVE TO BE on the lines of a halfstock English Sporting Rifle with a modern rubber recoil pad installed at a 13" L.O.P., and disguised as much as possible to resemble a traditional English, leather-covered buttpad.
In order to justify the cost of a build, not only comfort, but minimizing any long term damage to my shoulder joints MUST BE A PRIORITY. Historical Correctness be da**ed. Practicality Rules!!!!!!!!