The primary clutch is adjustable if you are above 7950 +/_ 100 rpm go down one click on your clutch to the 2 position if you are under RPM go up one click, adjust all three at the same time for about a 200 RPM change, the same as XM clutches. There are six positions in total and most clutches come in the unmarked (3) position to allow for about 400 RPM in either direction. Adjustment takes a couple of minutes and can be done using the bent key that is included. The owners manual describes this procedure clearly.
Hand warmers: the XM charging system wasn't putting out fully until in the upper RPM range (I don't recall what RPM was in the manual). Its possible that some are experiencing the same thing on the 850 if riding around more slowly. My warmers would only slightly warm up at idle but got much warmer very quickly once on the trail. Haven't picked up my shop manual yet and didn't check the owners manual.