I like wax and generally shun traction devices on longboards. Traction devices are great on shortboards and give a little boost on the tail for airs and slides, etc. As for spray on traction, it would be tough to make a product that doesn't junk up and survives different temperatures and conditions. In NorCal, we stay at 48-56 degrees F year round. SoCal temps vary wildly +-15 from day to day dependent on current and swell direction. High performance longboards like a Stewart LSP do well with tail patches, but noseriders with traction devices other than surf wax go over like a fart in church, or an FJ40 with 26" chromed rims and purple fuzzy dice. If wax isn't adhering to your epoxy board, stop buying crappy wax. Zog's Sex Wax with a proper coat of quick humps topped with an appropriate temperature top coat will stick well, or go with the Sticky Bumps brand as it works well on epoxy also. I used to surf a 9' SurfTech epoxy high performance longboard, and a Mickey Munoz 11' noserider epoxy and Zogs never failed to do the job. As for ripping chest hair out, a 4/3 fullsuit with 4way stretch neoprene solves that problem. Yeah, the cold sucks but we had 25-39' ridable waves at Mavericks this week. Ocean Beach San Francisco had double to triple overhead. Even the sheltered spots like Pillar Point Harbor Jetty, Half Moon Bay were putting up a clean 6-8'. I will keep the cold, big waves, and uncrowded conditions, and Florida can have the bikinis and flat water. You can't see the bikinis from the lineup anyway, and the wife more than satisfies! Good luck out there.
Ok, living in Colorado the closest I came to surfing is snowboarding. I sell competitive swim timing equipment for a living and we have a material that we use on touchpads that is adhesive and provided great grip when wet. Would it have an application for surfers? I know zilch about surfing.