Studs are high maintenance in outside rows and risk of track damage is high, heat exchanger damage etc.  Next time I just do it up middle. This time I bought a machine with ice ripper track. Can't wait to try it. Should be enough for how I ride 👌. 

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!!!