Bruce thanks for your reply. If I understood you correctly I really don't have to worry about the 77 load being too little, which is good news because the thought of digging 4 more posts was not a good one. Now on to the roof.....From what you said I'd be making a lot of work for myself having to build plywood walls and the such. I was not planning on having to do that but understand the reasoning. My goal was to have screening at least 5 ft down from the ceiling and perhaps even full length in some places. I did not want any solid walls at all. Now I know why those 12 ft aluminum enclosures sold for $800 need to be taken down every winter and maybe my idea is a pipedream after all.
I think I may have to either reduce the amount of the deck that is covered or find a different roofing material. If I reduced the area to a 12x12 ft being covered would I still need reinforced walls? Also I was wondering about fiberglass 'wavy' panels I've seen in stores? My wife doesn't like the look but if it means less framing on my part and less weight on top I think she'd understand. Also one thing I failed to mention is that due to the sloping of the yard I was planning on making a single sloped roof draining down to the back of the structure. I will put in a gutter and run the water away from the deck.
One final question....If I change to 2x6 joists ( I have lots left over from a torn down deck) and 2x8 beam/facia the psf goes down to 52. Do you think that's an acceptable number?