Without the mod my hanger did not slip off,however it did move far enuf to put excessive tension on the skin.I was trying to reduce this so that more of the effort goes in to stretching the actual structure and ligs.It seems to me that the matl which as you say is under the f/skin does 3 things
It pads out the head so that it is more difficult for the hanger to slip
It provides grip between the skin and head so that again it is difficult for the hanger to slide
The extra padding does make hanging more comfy.
As for extra weight I am not sure.I have not been using this mod for long.Without it I was at 21lb and climbing to try to overcome the skin effect that way.But now as the pressure is off the skin I have dropped back to 14lb.Bear in mind that all this weight is acting on the penis and not just part of it as b4.I will increase weight as I feel able as we all do.but now I feel that I am hanging more efficiently and not using what I think could be almost dangerous weight and pressures on my precious dick
Glad you found it interesting,let my know how it goes when you try it.