You can do a map on a small flat horn, or on a larger horn,say 12-15 inches, but somehow they don't look right on a smaller round horn. You flatten the horn yourself.
Talk to the suppliers on the phone and tell them the nature of your project. They have lots of experience in supplying horns and will do a much better job of sending you a horn that will work for you. Otherwise, a "cold" order by email simply is not going to give them the information they may need to do their best for you. :thumbsup: