Dicor self-leveling -- as the name implies -- is more free flowing than your typical caulk or silicone. It has the same viscosity when you apply it, but then over some period of time (an hour or two or?), it levels out, just like Frosty did when he got trapped in the greenhouse.
So I don't think it would be good for a vertical seal. It's great for laps -- like when a flange is sitting on another flat surface.
You can get 3M 4200 (and RV Proflex) on Amazon.
Yea, no one said those movers were cheap! But, like Bill said, none of your options are. Compare the cost of everything against monthly storage. Sometimes you can find a good deal on a used on though.
So if you only have 1/2" of clearance now, you need to come up with -- say 6 inches -- in new clearance, so that you have at least 3 inches per side. And even that will take some skill, but I deal with that much clearance on one side. I wonder if any more of that wood around the door opening could be removed and replaced with something else, like metal, so it still looks good and still provides a good seal. You might also be able to make that wood (or a metal replacement) removable, so that you pop out those sections when you need the extra clearance. Something that would take no more than 5-10 min to remove and reinstall.
I also seem to recall someone here on the forum having a similar problem years ago and made their awning easily removable. Does anyone else remember that, or am I making that up?
Dave