Hello I'm a heating and air contractor in alabama, I am installing a duct sysyem in the attic of a 70 year old house with plaster celings. I have done this before , but I am looking to a more productive way than I curantly e. I have been using a sawzaw (recipocating) with "Plaster" blades. They work well but sure takes a number of them. I have quite a few holes going in to this job. Is there another way?