I bought this product and have some questions: https://www.amazon.com/gp/product/B01KELTUAK Before I go to the trouble of installing this rig, I went to do some checks. The four way switch works as it should and smoothly. The pots though spin round and round. Is that an attribute of these type of pots? I've never seen a pot that didn't stop low and high. These sort of hit a snag but keep moving. If these aren't flat out bad pots out of the box, I'm not sure I'm going to dig them. That said, what other kinds of checks can I, or should I do before installation? I'm not finding much info out there on this subject.