It's nice to want to keep the Netherlands unified, but he kept trying to hold on to the South even after it was clear that Spain had re-establised a solid presence there. He should've cut his losses and focused on the northern states years earlier, imohmm IMHO I always have admired his (William the Silent's) quality of being a moderate and wanted to keep all the Netherlands together. And IIRC he converted twotimes, from Lutheran to Catholic and from Catholic to Calvinist.
The "much earlier" qualifier was intended to apply to both- I know he ultimately converted to Dutch Reformed, I just think he should've done it earlier as part of the process of casting off the South.