J, to be honest with you, none of the new Harley SE comps are holding up very well. That leads companies like Baker Transmissions in MI to design their own comp to sell against the HD units.
It's true that in the Harley style comp that if the Bellville washer spring packs do compress all the way, the two rotating ramps will NOT go past each other. So in the worst case it is direct drive.
As far as the Centa goes, I would go that route in a heartbeat. Bikes have been using rubber in the rear sprocket as a cush drive of sorts for years and Harley started with their cush drive in '08 as standard. It makes a huge difference on the Harleys in low speed parking lot riding. I've ridden both and prefer the rubber rear cush drive rear sprockets.
Centa has been making cush drives for decades and they use them in huge industrial power plants as well as huge diesel powered ships.
Even though it's possible IF the four rubber rods do go out, it would not be a metal to metal failure and only the rubber pieces would need to be replaced.
But from what I've researched, I don't see that happening any time soon. I've got 15k miles on my 1802cc 110" Harley and the rear cush drive rubbers are in as new condition when I had the rear wheel off for tire service.
You will get a "direct" drive with the Centa, albeit a slightly softer feel than with the Harley type.
I just feel that with the torque of the S&S 2L, you will never get a metal comp to last very long.
The Harley SE Rev 4 or 5 version, I've lost count, actually now has Torrington bearings in them and they use a new molded in oil deflector to direct the oil that's flinging around inside the primary case to drip back into the comp outer bearing. The constant flow of oil "seems" to be working better this time around. They also changed the ramp angles a bit.
My money would be to actually take the round rubber donut and stack about five of them in series so each would have its own twisting give motion and use them instead of either type of comp. I believe that if they're good enough for the larger series BMW sedans to use them as the differential to driveshaft coupling, it would be good enough for a 2L pulsating V-twin. Of course this is just my opinion.
I would think that at either end of the new comps in the M3W the splines should be locked and not allowed to "chuck" back and forth. I know the S&S flywheel side has a bolt through it into the crank, but I've not seen much in the parts catalog that connects the splined adapter to the stub transmission flywheel shaft. I see that there's a metal three forked hub that has a spline on the trans flywheel side but not sure how it's affixed to the trans flywheel stub shaft. I may be wrong and there is a substantial means of tightening the three fork adapter nice and tight. As far as the S&S side, on Harleys we torque the comp bolt down very tight and it's gets a dab of blue Loctite on its threads. You usually don't hear of any coming loose and when you do need to remove the comp bolt, it's a heck of a job to break them loose.
I'm very interested in your progress and love your updates.
I know I have no skin in the game here, but my money would be on the Centa versus any type of the metal type comp. Just because they're packed in grease, that doesn't mean the grease stays in contact to all of the wear surfaces. As some have said here that when their comp starts to rattle they shoot more grease into the comp through the hole in the bottom of the trans to motor housing. So that kind of leads me to believe that the metal comps need constant lube and grease is just not going to keep that constant contact thing going. Obviously you cannot have a fluid comp as that would be a very hard thing to pull off, but if you could, they may last longer.
So with all my rambling on and on and on... I've not been much help to you. I do wish you good luck and you're doing lots of people here a big favor showing them what they have inside their drivelines.
Have a great weekend.
