Any users of Z=Sleeves?

There's quite a range in thickness as well as price of ZCable's Z-Sleeves. Are there noticable benefits first of all, and if there are, do the benefits increase with the thickness? Whick ones give you the most bang for the bucks?
Hi David here, just got a couple of Z-sleevs and Im trying on my Audio Research gear with a Cary 306 player and Aerial- T10's. So far the larger sleeve will be staying hooked before my PS audio ultimate outlet. My system has more focus cleaner more rounded notes from top to bottom.
I feel liked Ive plugged the system into a Hydra conditioner. These tubes are a pain to use and I was unable to use them on my thick Kimber Bi-focal speaker wire
but had a smaller improvement on the Kimber select interconnects. Anyway the sleeves dont color compress or change the dynamics but things sound so much more natural.
I took the sleeve off and later in the evening sat down to listen but after 3 songs put the sleeve back in, Im sold I just dont know at this point how many more or where I will try these.