I suspect that the above ineffectiveness with slow stropping may be that with slow stropping the stroke is also of lighter pressure than with a fast stroke. I've watched the deflection of my strop when I strop slowly and it appears to be less than when I do it fast.

Once a new straight shaver gets his "sea legs" and becomes accustomed to stropping, the speed and pressure will work themselves out. One doesn't want to drive the blade into the leather, but at the same time, this business of only stropping with the weight of the razor on the leather doesn't work either.

good shaving,