I've done a bit of playing on cimbasso/contra for the Opera here for a while. It's really a heck of tool. That said, a couple pieces of advice:
1) Stay away from the small Cerveny. It's a bass trombone, and a terrible one at that. I've heard great things about the big one, but the small ones are absolute dogs unless you're playing Dvorak symphony 3rd parts. I've played 'em. Blech!
2) The Kalisons are great fun, and fabulous for a tubist. I'm sure the G&P ones will be equally fabulous.
3) I played on a cimbasso for a while which was a CC of my own construction, perhaps similar to Mr. Gnagey's (
http://www.jrdhome.force9.co.uk/cimbasso.htm" target="_blank" target="_blank). I really liked the tone, but it's challenging to manage Verdi on it. Puccini is very cool on a big cimbasso; but Verdi gets around, and is much higher. Look at Verdi's Otello and see what I mean. I'm sure Sam's Eb would be a great answer! I should've thought of it. But my CC (with BBb slides as well) is in the hands of a Seattle player now.
4) If you get a valved instrument, you may find you are renting it out. It's extra money, sure. But I found I wanted to be attached to the instrument, so I decided to...
5) Play a slide instrument. Couple reasons for this: First, the rest of the bone section is NOT playing with valves. Verdi's trombone sections were all valve instruments, and in Italy, the slide instrument just wasn't common in the pits. Now they are. Second, some of the cimbasso parts are actually serpent/ophicleide/bass-thingy parts, so unless you're planning to bring one of those, it makes no difference. Third, the bones will thank you for playing something which can more readily tune to them. Fourth, you'll be able to play contra parts as well, from Varesse to Wagner; more work! Last, you'll be hired to play, since most tubists won't be able to just rent your slide contra and play.
6) Barking is part of the gig, and the conductors are going to look to you to do that from time to time. But the majority of the time, you are to blend with the bones - Verdi's goal for the instrument.
7) Go for an F or Eb instrument. It’s more flexible, and less distant from the bones. The bass bone player isn’t on a valved F instrument; he’s on a slide Bb instrument. Get a little closer to ‘em!
My own instrument is an F/D/BBb/AAb instrument of my own design. I've used it for more than I planned, and I love it, my Quintet loves it, and my section mates love it. And the real honkers in the bottom end are too much fun!
Really, as a serious tubist with any opera opportunities, a tubist should own a cimbasso/contra. Verdi's Requiem (an ophicleide part, yes), overtures, Gabrieli quintets... so much music benefits from the addition/substitution/use of this instrument. Run, don’t walk!
J.c.S.
P.S. Ophicleides are cool too!
P.P.S. Sam, can you post a pic of your Cimbasso?