Go with the 166, it rides small and will float you even in the deepest powder. You'll be able to move it around easily.
YOu're getting a POWDER board--why get a 162 and then find its too short. Then have to sell, ship, take a loss, etc etc --just get the 166---in pow you wont even notice it.
Good luck--its a sick ride!
The Custom and Malolo have a few things in common in terms of materials and flex, but the Malolo has a 20mm taper.
At 215 lb, I'd say the 166 is better for your weight. If you have large feet, then the 166 is definitely the choice. Only get the 162 if you use a Medium Binder and the manueverability in trees is a super-high priority for you.