Collector gasket preference?

Using Percy's collector's (and head flanges) gaskets on Doug's headers. No leaks detected, just check once in awhile and re-tighten as needed. Being reusable is the best part, had the collector's off and on and still no leaks. I used the paper composite ones supplied with the headers for engine break-in and they didn't leak, but when swapping for the Percy's it was a ***** scraping off the baked on material.