Tony hasn't done any testing with the 850 and a Silber. Hoping he has a chance to come up with a killer package this winter.
The 56-42-36 helix suggestion was from one of the guys that works closely with Silber and runs a few 850's.
Again, no experience myself, but this was the Helix that was running well on the 800 also I believe.
We have run Silbers on 4 or 5 different 800's. Some do well with the recommended clutching, others seem to chew up belts or break springs. Silber included a helix in the kit until 2016.