i think that if single leg of pull of Friction Hitch of ProGrip, Taut Line, Tarbuck, Adjustable Grip Hitch etc. can have matching diameters and stiffness. Of full bodyweight powered hitch rigidity grabbing matching full bodyweight powered rope column grabbed rigidity of lifeline.
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Problem comes in if hang on dual end Friction Hitch, then host Lifeline is tensioned just as rigid by full bodyweight, but is gripped by Friction Hitch trying to impose, but each leg is only rigid from half bodyweight, not so imposing on greater rigidity especially at matching stiffness and size.
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Solution is to then reduce size of Friction Hitch cord to lifeline ratio,
To funnel half as loaded into shoe of denser/smaller footprint to compensate to more rigid against full loaded lifeline.
Usually also using stiffer cord to accentuate the effect, this all increases cord wear.
So thinking in terms of tension x stiffness divided by size of dispersed area so smaller cord is greater
vs. lifeline tension x stiffness divided by size of lifeline.
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Textures work in there too:
Rode a 1/2" in 3strand on arbo 12 and 16, 1/2" braids for years for very good grip and very long wearing , 12 strand nubbier, less round like stop sign for better grip but less smooth ride. Opposite of 16 rounder etc, faster ride..
The 3strand contact surface is unique compared to braids for this.
Evolved to 2leg pull varieties in 3/8" Tenex on 16 strand.
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When noted this was going with cord to be able to fold in half to match lifeline diameter but favored a bit more. So certainly can go with numbers offered.
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Always follow the forces,
And may they always be with you...