We got the rigging question answered from Garmin today. We are moving forward with the install, including the YD. In the grand scheme of things, the added cost is negligible. It's one of those things that if we don't do it now, we'll never go back and do it.
Art - you make a good point. Our Malibu had it and we all swore it was necessary. My buddy's Malibu doesn't have it, and he doesn't think it's necessary. His wife rides in the back and has never complained. That's his test. I don't ride in the back of planes, so for me it's not necessary. My wife rides in the WAY back of the 421 and has never complained. Maybe that's my test also.
I did cycle the YD (421) on and off yesterday during a bumpy descent and the difference was noticeable. Since the 421 is our people hauling machine, it makes more sense. The Ovation is used for the 1-2 person trips, so maybe not as critical. I have about 500 hours in K models and another 500 in the Ovation and the long body does have more tail wag for sure.
Don - you're absolutely right. I try to avoid those flights like the plague, but sometimes it can't be avoided.