Orchestration for tuba/baritone/trombone (also organ) from Robert King

Go to page 4, 2nd column for some useful thoughts about scoring for low brass (also for organ), specifically how to properly support low notes on tuba (or 16 ft pipes on organ).
http://www.trumpetguild.org/pdf/rareverettking.pdf

From the International Trumpet Guild: "An Interview with Robert King."

Robert King is a pioneer in the publication of music for brass. View his catalogue here: http://www.rkingmusic.com/