Years ago, I adopted the specs in the bulletin. Other local riders have also after I reported essentially no vibrations 90% of the time.
On our RTS, jacked under the frame so wheel is at full droop. Use the left side adjuster to establish belt tension at 140 pounds force or lbf, (this is different than a torque wrench setting of ftlb). Use the right side adjuster to align and track the belt. Once tension is set, make no other adjustments to the left side adjuster.
I suggest accomplishing this on a cool or cold belt and pulley in order to obtain a consistent setup anytime thereafter. While riding, the rear pulley will heat up and expand in diameter, altering tension setting slightly. Additionally, possibly the belt may vary when heated. Often belts will shrink slightly when heated. That said, best to accomplish prior to a ride.
We run no belt tensioner at all. Simply based on the KISS concept of one less item to fail unexpectedly AND no additional contact surface onto the belt.
Resetting the belt tension to 140 lbf certainly made the machine much more enjoyable on the highways.
As for the remark about this being a closely guarded secret here, probably not true. Can Am is the downfall of why bulletins are not released to the public, however, let me rephrase that, the consumer / owner is the reason Can Am does not release bulletins to the public. Having seen this before, the owners chat with their friends at breakfast, the owners convince the one owner all his woes are a cured by a certain service bulletin. That owner demands compliance with the bulletin for free and becomes relentless in pursuit of that. Hypothetically, the shop accomplishes the bulletin and the problem remains, from that point on it is a downward spiral of bad. Good shops know the bulletins, know the limits of the bulletins and will accomplish them on an as needed basis, not on a whim. Consider too, the technician and shop needs to get paid and if the bulletin accomplishment is declined the shop and tech worked for free.