i think its a question of trial and error, some people say combine devils claw with a good joint supplement can work but devils claw can have side effects as well. so get a blood test done once a year just to be sure.
I run an equine supplements business and produce a product called "Bute Substitute" so I should be able to give you some good advice. Most Bute substitutes are based on Devils claw but the amount of Devils claw can vary enormously. Our Bute Substitute contains 50% more Devils Clsw than "No Bute" yet it is cheaper. Bute substitutes are popular because there are known problems in feeding Bute long term especially with the liver and stomach.
I have tried LOADS, each of them over a long period too (as these things tend to take a while t work) and by far the best was Feedmark's Zerobute. Not cheap though