Quite frankly, I'm skeptical of friction hitches with any synthetics. Sheathing is (in part, at least) an attempt to overcome the inherent slipperiness of synthetics but comes with it's own shortcomings. Friction can be increased by increasing the contact area and/or by increasing the pressure between the two contacting surfaces. Unfortunately, increasing area tends to decrease pressure, so getting a net gain becomes a delicate balancing act. Delicate balancing acts are not my favorite entertainment on dark and stormy nights. That said, I do occasionally use friction hitches but most often as the final tie-off of a trucker's hitch. Hopefully, those with more experience using friction hitches with synthetics will chime in here. Fortunately, your post has already gotten the attention of Grizz, one of the forum's most authoritative on the topic of knots.