Good thoughts Lane and Sabotloader. Pretty much along the same lines as Ronlaughlin suggests.

I've pretty much resolved to go that way, probably with both a 1/8" flame channel from the primer side and a deep dish on the face of the plug, separated by a 3/16" long flash hole. Fortunately, I have a buddy with a lathe. I'll probably have plenty of time to get that done before the receiver assembly comes back from Dixon's.