I hear you but it is ok to jump on it once and a while to keep her honest and clean her out just don't rev to max rpms. By the sound of it you would rather have a mechanic work on your car if that is the case try and find someone familiar with Pontiacs Maybe join a local Pontiac club and network to find someone. To me if you are pulling decent and more importantly balanced compression and as long as your exhaust valves are not to tight I would just enjoy the car and not worry about it, after all it is not your daily that you have to absolutely rely on and you can deal with problems when and if they show up. Again if the mechanic who recommended the valve adjustment did so because of a proper diagnosis you can purchase a product called Polly locks to replace the stock lock nuts on your rocker arms and make them adjustable.