Jim, you''ll want to use a flattening agent (sold by all the mfgrs) for horizontal surfaces (deck, cabin top) to kill the glare. In addition, you''ll want to add non-skid material of some kind (there are many choices) to all the non-skid areas.
I''ve used lots of Brightside and also Interthane from International and don''t think Brightside will produce a long-lasting finish...altho'' I''m sure it can be made to look nice from a few feet away when first applied. The 2-part polyurethanes are far more wear-resistant and, altho'' more costly and a bit more of a hassle to prepare, no harder to apply and will carry the cost of their application for a longer period of time.
Be sure to use both the manufacturer''s educational materials and their 800#; there are lots of niggly details, each of which will contribute to a better (or worse) result.