Rob,
I have a reamer,but no FFL. If you or your "agent" can bring the drilling to me, it would only take 5 minutes to do the work, and I have a place within a short drive to try it out.Whether it is worth it, to avoid handloading(keep in mind that you can use standard dies after fireforming cases)is entirely up to you. The upside is that the work won't cost you anything. For whatever it is worth,I don't consider the chamber work an alteration since it wouldn't change any of the markings.
Mike