I have some hifax if you need it. This is the material used in the rear skid frame of snowmobiles. It is sold at a lot of the aftermarket snowmobile parts places. I was going to use it on mine (87) but thought it may be to slippery so I tried to use a piece off the big end of a rubber bungee. Any snowmobile shop would likely have a used piece of it they could give you too.
The rubber bungee thingy worked for a while but now I think it was too soft and wore down. I now use a rubber bungee section about 1.5" long with a half circle cut in the middle. I loosened the housing, then sqeezed this piece between the housings, then tightened the housing screws. Works ok.
I may try the hifax thing later. I have the original form for the little spring loaded thingy, I think. That is what I modeled my first part after.
Oh, and I read a few years ago that someone had used a feeler gauge piece, putting that on the handlebar first, but I can't recall if you had to have some semlance of an original friction block to rub it.