You have not yet understood anything of this friction hitch, have you ? 
It has NOTHING to do with the size of the cordage, or the size of the load !
In looking back over this thread,
I'm quite dismayed to see that apparently the OP has
been changed --the presented images, no less, about
which subsequent posts remarked. This renders reading
comments such as
Scott says "I just tried this affair out" and that sounds
too singular for the plurality of ideas put forward already!?
In Xarax's bottom-shown structure that comprises a strangle
anchor with then interlocked, opp.-handed half-hitch turns,
and then the seemingly neat "cloverhand" final component,
fruitless --as NOW there is a set of photos of one structure,
not the several about which discussion developed and ideas
flowed.
Which throws would-be commenters some doubt about making
comments, if history is to be revised like this.

Now, to the point of my understanding --expanding it--,
I've put to some test nearly equal-sized cordage with some
body weight upon ONE of the versions of the "ww hitch"
shown. Indeed, I'm seeing some gripping I'd doubted
would obtain, with such cordage sizes (as though that
mattered). I'm not convinced of the behavior in slicker
ropes yet, but impressed enough to look further.
(beachcombed 5/16" mod-soft-laid polyDAC hitched
around 9mm? marine kermantle (aged-frictive), with
the latter tensioned via pulley & tied off.
An obvious antagonist to a climber is how much *retreat*
--extension of the structure upon loading-- must be given
in order to achieve grip! As though to give the painful
maxim "For every foot forwards, a half-foot back!" My
hitch released pretty nicely (gripping w/o jamming),
but there is relatively much extension ("retreat") to
come upon re-loading it. For some uses, this might
not matter; for getting from below to above as quickly
and easily as feasible, it matters much.
--dl*
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