Richard,
I'll mention that for the first 20 or so years that I owned my Pagoda, I took it to various mechanics along the way, asking them to fix an issue of rough running above 3500 rpm. It wasn't serious, but it bothered me for 20 years.
I eventually worked up the 'courage' to do the linkage tour and was able to get the car running better than all those mechanics. And it wasn't all that hard to boot. I strongly encourage you to have a go at it it.
Of course, I will also mention that after Dan Caron (Benz Dr) had a go at it, it ran even better. The car is pure pleasure to drive on the open road when it's well tuned. So you can have it done by someone, but make sure you pick someone who knows these cars.
Meyer