Medium, unless youre going overnight a lot...!
I paddle a large, and it is correct for me at 235lbs. I also do self support.. although sadly pretty infrequently... we will see how that works with the Lg zen. It has 10gal less volume then the superhero.
Straight from the employees/team, JK sizing is generous. (i am well above suggested range of 220 lbs for a 4fun or superstar, and those boats have both worked out great for me...) of course, you got to actually demo, to see how it feels.