Late to the party. Feel free to email me for more info. firstname.lastname@example.org
The IRS is a high volume board. I don't know the volume I need to figure it out. My friend G-mo has been riding it at 240. But my son loves it too and he weighs 105 because it's light. Inflatables don't turn on the rail like a surf board they basically just turn on the fins. That said I have been really stoked with how the IRS surfs. I am 165 and I can paddle it down class II.
The Cobra was designed to make smaller waves more fun especially for bigger guys but again I'm only 165 and I mostly ride the Cobra anymore. It is also high volume. I have that number in my computer I could post it tomorrow. For me it alows me to spin and do tricks more easily than any board ever.
The river surfers are a more traditional shape. I ride the 8'0 mostly when the water is up. My partner Zack almost exclusively rides the 6'11. At your size I would think the 8'0 would be a better choice but only really during higher flows. The Cobra or IRS would be fun for the rest of the season.
The comments about not having a surf board feel are interesting...that's kind of the whole point. If traditional surf shapes worked well on the river we never would have started shaping boards 8 years ago. Most river waves are so much smaller and less powerful than even small ocean surf and the mechanism of surfing is very different. Our boards are designed for the type of surfing most people have access to for most of the season. When Glenwood is over 20k or Pipeline or some flood stage wave on the front range you can plane out on almost any board. We've been trying to help people extend the river surfing season.
i won't be in Golden this weekend, going to the grand opening in Montrose but some of our team guys will have IRS's to demo. Thanks.