Been deliberately staying out of this thread since I am a representative for Panamorph, but I just wanted to point out that the UH480 is a cylindrical / prism hybrid, a design unique to Panamorph. It is not a simple prism based lens.
I have been there for two separate blind shootouts between an Isco III and a UH480. Viewers were asked to rate their preference with video content, and then with test patterns. With video content, the results were consistent with random chance. There was no clear preference for either lens. With test patterns, the Isco showed slightly less pincushion at certain throws than the 480 (slightly less than 1/8 of an inch with a 16.5' throw to a 144" diagonal 2.35:1 screen), but most thought the 480 had slightly better contrast. Everyone agreed that the lenses were equally sharp edge to edge.
I have not seen the 6000, so can't comment upon it. There is one factor here in its favor, in that your projector is 12.5' away from the screen. The absolute sweet spot of the UH480 is 14.5 - 17.5 feet, and you are slightly closer than that. Our testing of the UH480 shows that its true usable range is about 12 - 20 feet with no notable loss of sharpness with standard video content, but if you were to bring up a test pattern that resolved single pixels and got up close to the screen, you might notice a slight softness.
I see that the HD6000 can supposedly focus down to two meters. If that is indeed the case, you might see a slightly sharper image with it at the pixel level. I do want to point out, though, that even though certain pure cylindrical lenses have a variable focus vs. the fixed focus of the UH480, it is also true that every lens has a specific sweet spot in which it works best. Having a variable focus just means that you can get more satisfactory results even if you navigate away from that sweet spot. With the UH480, the lens can have a variety of sweet spots depending on what throw we build it for. The stock UH480 has a sweet spot of 14.5 - 17.5 feet. We can build one with a different sweet spot, but it does add $1K to the price of the lens.
I can say this definitively - the UH480 has pin-sharp focus out to the edges of the screen, so if that is your concern the UH480 should solve that problem for you.