Welcome Mr Clean. I've been playing Pressurewounds since 2011 on both my Jazz Bass and a G&L L2500. What I can tell you is that from a perspective of feel against the fingers they are far smoother than any round I've ever played and also smoother feeling than a ground wound like GHS Brite Flats. This may help.
WHAT IS THE DIFFERENCE BETWEEN BRITE FLATS AND PRESSUREWOUNDS?
Both strings use Alloy 52 (a highly magnetic nickel-iron alloy) for the cover wraps, and have our signature core-to-cover ratio. However, the main difference is that the Brite Flats are wound like a roundwound string, and then ground smooth. This allows them to retain some of the clarity and punch of roundwound strings, but feel like flatwounds.
In contrast, Pressurewounds have the final cover wrap run through two rollers during the winding process, which squeezes the string to more of an oval shape. This retains the roundwound character, but gives a smoother feel and a mellower sound; new, these sound like a set of rounds after a couple of weeks of playing.
I would actually disagree that the Brite Flats feel like a flatwound. I play LaBella Flats on my PBass and GHS Preclusions Flats on my G&L Kiloton and both have a much smoother feel and mellower tonality than Brite Flats which sound like a mellower round wound and simply feel like what they are. Are round wound that's been given a flat top.
IME Pressurewounds have a very unique feel and tonality to them. They're very tonally expressive, dynamic, very articulate and on the mellower end of a round wound scale but still provide that kind of "growl" I enjoy. And while I feel the winding' my fingers glide over them without friction or significant finger noise. I also prefer them to tapewounds.
I feel the illustration on the packaging provides the clearest look at how the string is constructed and what the outer wrap is like.
To me this is an even better comparison of the profiles of outer wraps on Compressions Wound/GHS Pressurewound (same string) vs a Round Wound or a Half Round/Ground Wound. Most of the characteristics of a Roundwound are there in a Pressurewound but without the zing or the string feel and noise.
Hope this helps.