Other than perhaps being a bit ponderous there is nothing wrong with what you are doing. Certainly it is NOT cheating. The rule your pro was referring to was Rule 16 - 1 a. Touching Line of Putt. It states "The line of putt must not be touched except:" then lists a few exceptions which I won't list here as you obviously have access to a rule book and can look up Rule 16. If what you do helps you putt, go for it.