A needle point axle in a properly made bushing will have much lower rotational resistance than a blunt end axle. The question is will that make a difference when running the trains? I have never tried retrofitting the bushings with needle point axles for two simple reasons. I have always operated link coupler equipment with the sheet metal sideframes and the layouts I had were small enough that the layout size limited how many cars I could use. When I get my new permanent layout later this year I will be able to operate much longer trains. After setup I intend to try some "pointy axle" retrofits to determine for myself if it makes a difference. What I suspect will be the case is that I will be able to pull 30 freight cars around the layout with the Flyonel Challengers, BigBoy, YS 3 and Mikado regardless of the wheelsets used.