Use a pattern that allows you to add more if you feel the need down the road.  where you ride and how you ride imo dictate what you need.

Comes down to personal preference. You can run none and be "fine" with it.   I remember guys running less than 192 on their 800's,  I always ran 192 and would never settle for less. Recommendations would be based  on riding style, conditions, and preference.         

Maps Rule!!!

On my Polaris 850’s I have run 2 per row.  Both on a 137 and 146.   Lots of traction and no pull outs      I have rode with la few ZR 9000 and Sidewinders with 2 per row and no issues.  Lots of traction.   What does dealer recommend?    I think 4-2-4 would be way too many.  Are you changing to a more aggressive ski to turn it?