There is an exhaustive thread about this topic https://forums.pelicanparts.com/911-engine-rebuilding-forum/137346-re-ring-alusils.html. After reading through it along with several others and on the advice of the mechanic who reconditioned my heads I honed the cylinders with a silicon ball hone and put new Goetze rings on. The rings seated immediately and I get no smoke on startup other than the occasional time when the car has sat a while. The mechanic who gave me the recommendation said he got it from a friend in the trade who is a long-time mechanic for one of the very well recognized Porsche race teams. He said that before he got this advice he had re-used a set of Alusil P&C with new rings for his own SC. Told me it took a year for the rings to finally seat but eventually they did. Just my experience and YMMV.