RE: do it yourself arrow spinner
Tools don't need to be complex to be efficient. Good thinking about your homemade spinner. How much did you spend?
I made a spinner a few years ago using four marbles and an 18" piece of 2x2 hardwood. Just drilled two side-by-side shallow holes at each end and hot glued the marbles into the holes so that a little more than half a globe was exposed. With just a bit of hand pressure on the shaft, arrows spun well when nestled between the two slick glass marbles.
Keep on thinking and building.