So, I am shooting a Lehigh/Knight breech plug and I am using normal - non-mag - primers. Win W209's. I shoot 20 shots quite often when bench shooting without any problems. I guess after 30 shots I would use a long 'bit on a stick' to hand drill out the flame channel of the BP. No need to remove the plug.
I use only Teflon tape, but I use the Blue Monster - blue Teflon tape - I have found it to far more durable than regular white tape or even the thicker pink tape.
Wrapping the plug in the correct direction is really an important point.
But it should be noted that when shooting BH it really isn't necessary to wrap the plug. I do it hoping that it reduce any gas cutting that might occur from shooting BH