What I do is disconnect the spinner from the switch below the play field and try to tweak it for a balanced spin. A couple of times I have had to adjust the spinner switch blade: Too much tension on the switch blade pulls on the spinner and slows it down. Too little tension and the blade will push the bottom of the spinner fore or aft.
In one case, I had to relocate the spinner switch on the bottom of the play field to get the proper rest position.