Ya Nis, with the choices/options, i would get the BX if it's easier to get and add 5 gal's.of Perlite to the bale. Between Sunshine and Promix....always go with what's closest to our goal. Does the BX have Myco in it...or not. If not you may consider inquiring adding a bit to the mix too. But i would get the Promix. Cheers Nis , and gang. Those "complete mixes " you def. wanna stay away from OK! The Kit must be used "pure" as designed...that's when it "shines" . Cheers and Happy New Year everyone.