Thanksgiving day was actually warm enough that I decided to try out the forever black dye that I ordered earlier in this thread. The results so far are mixed, but promising.
The regular trim dye is too watery and the applicator sponge is WAY too small.
I ended up draining a bottle of the dye into a paper cup and using a tire-cleaner sponge to apply it to the cladding. Even then, the main problem was that it was very streaky. For some reason, it likes to run from the top of each panel and leave vertical streaks - plus streaks from the sponge strokes. I gave it about two coats and it looked somewhat OK.
Later that night it rained a small bit and the next day the cladding was only slightly more streaky than it had looked before the rain. The extra streakiness might even have just been the result of fully drying out.
So, I took the tire-gel version of the dye and applied THAT to the clading. Using the gel works a whole lot better. It was still a little streaky, but two applications pretty much took care of it. Of course this is over two coats of the regular stuff, so it maybe it would take 3 coats of gel if you were starting fresh. But, the gel is really easy to put on, I can do one entire VX in about 10 minutes with the gel where using the regular dye took about an hour to do one coat, even with a big, tire-gel-sized sponge.
The both the gel and the regular dye dry to the touch in 20-40 minutes. Even after dry, the clading still has that "glistening wet" look.
I will report back in a few weeks to let everyone know how it holds up to new england winter weather. Given how well the regular dye handled the rain, I've got high hopes for this final gel-based coat.
But, if anyone else is contemplating giving it a try, my advice so far is to skip the regular dye and go with the tire gel 100%. Also, be sure to wear a latex glove, the dye will wash off your skin easily enough but it really sticks to your fingernails, particularly beneath your fingernails. My right hand still looks a little goth as I type this.