I had called Chuck before I posted this and he didn't really know. He didn't know why there were 3+ options covering the same model range and just said to try to measure again or use a template kit. I figured plenty of people here have SeaDeks as well as something with the same platform as a 2006 OBV so wouldn't hurt to ask.

That said since I hadn't heard anything for a while I just took a chance on the 69 3/16 x 25 9/16 platform and that appears to be correct.