Really focus on diet, losing weight is going to help you considerably.  It sounds like you are trying, and 10 miles is all fine and good, but you should work on extending that, and look at how much effort you are putting into the bike.  When I cycle outdoors I typically do ~25 miles, and it takes me 1.75 hours.  To burn the same calories on my stationary bike (just a fixie with a friction stand) it takes 2 hours, and it's constant peddling, where when I ride my bike there are lots of moments of coasting, etc, but also more intense or grueling segments. 

Ideally you want to be able to do pull ups, that should be your goal.  Like being able to bust out 10 pull ups in a row signifies pretty ideal (really simplified) surf shape for me, because it has the back/arms as well as the lack of weight to lift.  

I think the wavestorm is fine.  If they put weight limits on boards I would be over all of them I'm pretty sure.  And, I've weighed 195 lbs for a minute and surfed lots of boards still, including 8' foam boards, but I don't know if I was specifically surfing any wavestorms (there's a difference that you shouldn't worry about).  

Like, I think your problem is going to be cardio, and it'll just take time getting into shape, be patient, but don't stop getting your ass beat by the ocean, it'll make you a better surfer in the end by just punishing yourself like that, and having that hands on experience in the water, it'll also just make you more comfortable.  

I knew a dude who was taller but like 300 or so lbs and I would always put him out on a 10' foam board that was giantic.  This man was a beast though.