I have installed, repaired, and taken down many of these doors and here's what I can tell you.
You can do it yourself. To save money, purchase the vinyl strip material by the roll and not as a kit. In addition to the website you found, the vinyl strip doors and rolls can be sourced through Grainger and McMaster Carr. You can make your own hangers using perhaps the door header, depending on its construction, or drilling and tapping some angle (aluminum would be the easiest to work with). The roll of vinyl strip material I would use would be the products with the ribs in them. They stay clearer longer. This is especially true with the relatively light use your personal building will have as opposed to an industrial application where 100 forklift trips are made per day. Now don't me wrong, the strips will eventually cloud up but yours will last a good while. If one strips is torn down, it is easily replacable. Make sure you don't cut the strips too short when they are installed. Also, the ribs let the vinyl not stick to one another as easily as the solid material. And yes they will stick some but that's good because its keeping the hot side hot and cold side cold. As far as cold weather, since you are in Tampa (I think) you should have no problem. I have no experience with the product in the harsh environs of, say Duluth, Minnesota, but have noticed that the strips do stiffen slightly as the temperature decreases. As far as fire goes, these vinyl curtains will burn. And when they burn, they give off a horrible black pungent cloud of bad karma. Ask me how I know.
So really, is this the solution for your problem? Hard to say but perhaps you could try one door to see if you liked the fit, the performance, and the cost. Or maybe an alternative solution would be to just try to close up the gaps you have rather than seal the entire opening. If I understood correctly, the gap you have is no more than 3/4". A wide weatherstriping product might better suite your needs and be much cheaper.
By the way, neat building. The wall panels look solid, not the typical metal sheating. What are they made of?
I was just in Tampa last week. My college roommate is the new Base Commander at McDill and I got to attend the Change of Command Ceremony. Very impressive.
Good Luck.
