i've L-earned a lot from some of ol'Justin's in-sights over the years.
i think the Uni; would be overkill for us in amount of turns/bulk. A short coming could be the way the final Bitters sticks out to the side; nor is as immediately clamped down on by as much Standing Tension Part force as possible to secure self. Here the Standing Tension Part, doesn't take it's turns immediately around itself after device is in bight/eye that is forming, but rather travels up, and then takes it's turns. i'd think the subsequent turns around both parts of line would buffer the force to the turns. On the flipside, the Scaffold-Dbl. Noose.-Dbl. Fisher Persons Hitch takes force from the Standing Tension Part and immediately uses that force to secure after the devices in the bight/forming eye.
Because of the sideward/sore thumb sticking out of the final Bitters and the less immediate clamping down to secure with the finite/available Standing Tension Part force (as the Equal/Opposite; initiating force to the lock of the hitch); extra time, weight and materials; i'd stick with the proven for this use, in these materials/braids/diameters Scaffold/Dbl.Noose etc. knot.
Also, noting that in neither case should a Round Turn be placed on the device; rather than a Simple Turn (even though usually replacing any Simple Turn with a Round Turn would be an up grade like Over Hand Knot to an Anchor Hitch etc.); for the increased friction on device would reduce securing force to the Turns in Bitters and any possible shock absorbing capability that could be added.
i think also that the Turns around own Standing Tension Part in these hitches is superior to turns around a host device to secure (Clove etc.) in that the coils could give A) some extra line like 'spring' to relieve some impact forces and B) firm the 'throat' of the Standing Tension Part like some electrical strain reliefs; to strengthen against angled pulls and firm against breaking from the maximum force of Standing Tension Part flowing into the first arc/bend. Perhaps the Uni would give more shock absorption capability; but the possible firming of the throat i'd think would be better in the most immediate force usage of the Scaffold/Dbl.Noos...
If desiring a 4+ turn climbing/rigging hitch; i'd consider a Blake's (Dbl.Noose + 2 more turns that don't trap Bitters/tail) or 4 turn Scaffold/Dbl.N.. etc. knot/hitch.
i passed it along to a ScoutMaster - his jaw dropped when he saw the knot tying sequences, tried it with his group and could'nt believe how much easier it was to teach them.
