Euro is all I have been using for the last 5 or 6 years. I've used universal on occasion, but mostly Euro now. I had a car come back for some repairs a few months ago that I painted back in 2019. I noticed some primer/bodywork shrinkage on one part of the car. I just buzzed it with 1500/2000 and it buffed out like nothing, so I guess I am kind of unclear about the whole buffing window deal.