I have a powermatic 60 b 8" jointer with knives. Before replacing the knives which from what I have read is not an easy task, I thought I would look into a helical cutter head. Opinions of these helical cutter heads vary wildly. Will someone try and guide me in the right direction please. Should I go with new knives, a helical head or perhaps use the money towards a bigger better jointer . Thank you in advance for any help.