You should be able to use your existing breech plug just fine. Follow the recommendations from the BH website in regard to primers. It needs to be HOT to burn the powder. I use European shotgun primers as they are .001 bigger in diameter than US made 209's. Tight fit, hot and less gas blow back, but ONLY when using BH powder.
TC breech plugs have an 1/8th inch flash channel. An 1/8th drill but works great to clean them out USED IN THE FINGERS ONLY! Some of the big shooters I know that use BH 209, drill the flash channel out to 3/16" on their TC's. Obviously, they have decided to use BH exclusively.
If you go with BH, your shot to shot cleaning procedure will change. Use a smokeless powder solvent barrel cleaner. I still like to swab between shots but when using BH, it's mainly to remove the plastic residue left behind by the sabot.
Hope this helps, and all the best,
Birch