On my 701 I converted the split rims from tube type to tubeless with a kit right from Zenith. It was nothing more than a gasket between the halves and a rubber O ring seal that was lubricated to seal the over the gap on the inside where the halves met. Then just popped in a tubeless valve stem and it was good to go. I changed them over after slipping a tire on the rim and cutting the valve stem on a landing away from home late one winter afternoon just ahead of a snow storm. The right combination of cell phones and mothers got me out of a cold walk.

The 26" are wider on the track than the 8.50's and will rub the sides of the Datum ski. The 8.50's barely work in width and height.

The 26" blimpies are noticably larger than 850's.
I know some people have talked about using liquid bedliner as tire dressing on their BW's. I wonder if you could use it to fill in the grooves on an 850 to reduce rock-throwing?

i think we need to design cost affordable set of mud/rock flaps for all birds. the stuff currently available is huge dollars...gotta be a way to do it for maybe a couple hundred...?!