The 906's are shorter but stiff so a softer stock length shock is required if you want a smoother ride. If you were using the LC shocks with those they are way too long. The 890's are taller but can be bouncy without some weight in the back or a stiffer shock from a heavier truck like a 4th gen or LC. Now to confuse you more, 890's will sag overtime if you put a lot of weight in the back like an aftermarket bumper with tire carrier. Also your stance loaded and unloaded might be important to you. Just think about the future mods you have planned where you will be adding weight. You dont want to do your lift a second time. I read hundreds of lift threads for a year before I decided I what my best options would be. Those lift threads have opinions from owners that have used all kinds of combo's and you can learn a lot from guys that have redone their lifts 2 and 3 times! LOL Dont forget tires have a big effect on ride quality. E rated truck tires ride like shit on our rigs. But if you have a short ride to the trail, dont DD it and wheel every weekend they're gonna be fine. If you're mostly a pavement princess, pass or C rated tires would be better. I have pass rated HWY tires on my Limited because it never goes off road. They're quiet, comfortable and get great MPGs. My lifted 4runner has D rated mud tires because its 50/50 pavement/off road and I have very long drives to the trails. Good Luck!

PS: Thousands of forum members here have used 4th gen Bilsteins with 890's over the years with no issues. I dont see why the Dobninsons would be a problem?