So my bulk Munich choices right now are Gambrinus 10L for $35 or Fawcett Munich for $45. Which should I go with? This would be used in American ales and altbiers and possibly a märzen or schwarzbier.
Not sure it much matters for throwing 10% in an American Ale.
For making German styles I would say figure out how to get German malt but Gordon Biersch uses the Gambrinus and their dunkle is more than acceptable, so I can recommend the Gambrinus based on that indirect experience.
If you hadn't guessed based on the name, Gambrinus maltings does have German roots.