I stopped using gasket sealers in most applications years ago after spending an ungodly amount of time trying to scrape all of that crap off mating surfaces. What I do now is make sure mating surfaces are very clean, flat and free of any nicks, scrapes or dings, then lightly coat those surfaces, and both sides of the gaskets with a chassis lube type grease, then bolt it together. The initial preparation of mating surfaces is a key factor in achieving a good seal.
I rebuilt the rear in my avatar 35 fordor last May using this procedure and it is dry as a bone on all exterior surfaces today.