Maynard also played French horn alot, back to the topic, I've marched all of the horns (tuba, mello, bari, sop) I'm normally a trumpet player, the biggrst problem I ran into was going big (tuba) to small (trumpet) at the same time(less then 5 mins between) My lips just wouldnt buzz on the smaller piece for about an hour, after that it was fine, your muscles just develop differently for different horns, also, playing low brass will REALLY help your air use, and tone on all of the horns.