All of those materials, alas, are far from ideal for sound deadening in an infinite-baffle application. The cabinet is small, true, but it is not too small; Bozak sold smaller bookshelf units, like the B-313 and B-502. While those were arguably too small for a B-199 (about 2 cu ft instead of the requisite 5 cu ft), Bozak used a similar padding/curtain layout, just scaled down. It will work, but the bass will not be as low as the larger variants. I suggest you discard the UltraTouch in favor of cotton batting. When Biggles had his problems with his B-302 project and was ready to give up, I suggested he replace all of the Ultratouch and move to a swinging curtain using upholstery batting. This completely solved the problems. Others have had similar results. The core issue here is that UltraTouch is far too dense and has no loft. I cannot say if this is a consequence of the factory compression for shipment, or inherent in a ground-up cotton instead of fiber approach, but it is a problem. Since UltraTouch is a dense mass it lacks interior voids crucial for sound deadening. It really is totally unsuitable for damping on a speaker cabinet, particularly an infinite baffle cabinet requiring a loose curtain . Again, Biggles will confirm this for you, as will others who had similar experiences. The curtain is a key part of the Bozak infinite-baffle cabinet. The outside of the flowerpot is less critical, but the goal is to remove all interior reflections and ensure the backwave is lost. This is why Bozak covered the crossover with a piece of batting. Many times these interior reflections will result in resonant peaks which cause non-linear behavior that degrades the quality of the audio, anywhere from suble to substantial. The short distance likely does not matter because it is at the top. As long as the curtain remains free to move, all should be good. The pressure waves will migrate around it. The point is to lose the backwave so it can't bounce off the sides and rears to return. That's what the curtain does. I suggest re-creating the interior of a B-302 and repeating your testing. Using software which will generate an SPL plot may show you details which you cannot easily distinguish by ear.