Oddly, that helps!
I think I'm getting more confused about how all the organizations interact. Sounds like there's no 501st restriction (i.e., I could get a TK designation even with an FX bucket), but the FISD is currently providing recommendations for more consistent/authentic armor (for obvious reasons). Does that sound right?
Either way, my MRCE should arrive next week (and the FX will be a good practice run build).
This CRL is a great idea, by the way, especially for trooper-hopefuls like myself.
Thanks