I also prefer BH209. It's all I use in my Accuras. I shoot enough that I buy it in the 5 lb jug and it is very cost effective. I have shot 60 consecutive shots without swabbing. I do clean the flash channel in the breech plug with a 1/8" drill bit in a pin vise. If you order the BH209 breech plug from Western Powders, it will come with one. I never touch the flash hole in the breech plug. I've never seen a need to clean it and if you do so, you take the chance of prematurely enlarging it. I have never used anything but 2 drops of Lucas gun oil on my breech plugs and have never had an issue with removing them. They always screw out easily with 2 fingers and are clean, with no fouling. If the breech plug was originally installed correctly so that it pressure formed the inner lip into a seal, it will never leak.
A caution on using teflon tape. I had a friend that used teflon tape on a CVA breech plug and the plug was leaking badly. Upon inspection, it appeared that when he removed the breech plug earlier, some of the tape stayed in the threads of the barrel and when he reinstalled the plug, it pushed that residual tape down to the bottom of the threads, keeping the breech plug from seating completely so the inner lip did not seal. As I said, it's not needed on the CVA QRBP but if you do use it, make sure you get all the old tape cleaned out of the breech threads before reinstalling the plug.