Lots of Questions!
OK, Marden,yours first.
Like any hitch it should be set and tested before heading up. This hitch is best suited for more supple E2E cords such most of the 12-strands (tenex, ice, etc).
Usually once set it stays put and works predictably.
If used with the hitch climber you do need to be careful about the climbing rope termination. Spliced eye is best as it won't catch the hitch at all. Anchor hitch seems to be the next safest bet. I've had very, very few slips from that termination. Bulkier terminations such as DFK, Buntline and others definitely will send you for a ride if you aren't paying attention.
If you use a knot for termination you might want to consider not using the hitch climber system.
The cord used in the pics is IceTail with self spliced double locking Brummel eyes. I use an extra long E2E with a full crossover bury of the tails.
Once was I weighed well over 250# and couldn't get enough wraps out of a standard length E2E so I started climbing on custom made 36" E2Es. I'm 185# now and just never gave up the long leash.
I have tried it with one double braid E2E I had on hand. (got it at geezers last year) It was a brand-new and a very stiff cord.
Needless to say it didn't automatically grip without manually setting it every time I stopped. On the other hand it self tended and pulley tended flawlessly.
So, with a stiffer cord, I'd have to say it was unpredictable. Perhaps with a broken in cord it might have done better.
So, Jimmy, it does self tend quite well, though I do not use it that way. I always back it with a tending pulley.
Mac, indeed it did come from my failed attempts at the knut and the mic...mih...mihk...that darned mexican-knot.
BTW, Mac, This is that silly knot I tried to show you at NEG last year! Maybe Shelter Tree will have a setup like last year and you can run the hitch for a while. If so I'll show you then. You too TTM if you are interested.
YoYo, that ability to snug or loosen is exactly what turns me on to this hitch. When was I a fatboy my hitches (Schwabish, distel, MT, VT, Blake's)were forever seizing or too loose.
That little "overhand" action on this hitch keeps everything in place also means that in most cases if you make too few or too many wraps you don't need to retie, just adjust the "snug".
Since it doesn't seem to seize, there is no need to worry about "breaking" it either.
Limbwalker, I like the description of a hive, It certainly looks like one! Even so the company name is pronounced "Eevairnon" as it comes the french word Hiver, for winter.
Anyhow, hope that answers your questions. Meantime, I'll give it a little while longer to see if someone knows whether this knot has been named before and if "knot" I'll name it!