i've been using padded endless low strand count hmpe strings for decades. no, not for 'speed', for consistency.
'skinny strings' require the use of hmpe (you know, 'fast flight', 'dyneema', '450+', etc) and not polyester (you know, 'dacron', 'b50', etc.) simply because the typical hmpe strand will exceed 100# of tensile strength and the best dacron will be 50# (but usually less).
at most, a good and way overly safe tensile strength bowstring formula is 12 x the bow's holding weight. some folks go down to 10 or even 5 x the holding weight.
a 43# bow (12sx43# = 516#) needs a minimum of 12 strands of dacron polyester (12Sx45# = 540#). that holding weight would also be fine at 10 dacron strands (10Sx45# = 450#). or 6 strands of hmpe polyethylene (6Sx100# = 600#). add to the mix the durability factor, so low count hmpe strings might be better served by adding two more strands to the count (8Sx100# = 800#).
for my 55# longbows i use my own 8 strand d'02 endless strings exclusively. each loop is padded with 4 strands of dacron and i use #4 nylon for the loop padding and .019" halo spectra center serving (man, is that stuff tuff!). 12sx55# = 660# (the tensile strength that needs to be met). 8Sx100# = 800# (the tensile strength of 8 strands of d'02). 800#! even with only 8 strands that's a heckuva strong bowstring!
i just replaced a nearly 3 year old skinny string on one of my longbows. it was used for 5 hunts, drug through the bush and swamps, three dead hogs, and many many hundreds of arrows pushed by it. save for a slight unravel of the halo center serving, the string is in great shape and i'll save it for a back up.
imo, a side benefit of low strand count hmpe bowstrings is that you do get some 'string spring' simply because yer cutting down the typical mega high tensile strength strand count down by 50% (8 strands versus 12 strands). however, the creep and continued stretch of hmpe is severely limited.
so, to recap - i believe that 'skinny strings' offer the following benefits ...
* consistent low to no stretch/creep
* some measure of elasticity on release that's good for the bow
* low noise on release
try one, give it a good workout.