In Tom's defense, there are numerous Rudy Meinl and Meinl Weston tubas that have second valve slide triggers worked by the left hand. This is particularly useful for the 2-4 combination, where many tubists often choose to not use the fifth valve and instead have to pull 4 or 2.
After doing something similar to Tom's setup on a Bohm and Meinl CC, I had a repairman add a long oval shaped brass loop to the top of the slide to replace the round ring. If I can find a pitcure of it out there, I will post it. I had the ring on my Mirafone 1290 rotated 90 degrees to allow easy pulling. My current CC actually has a factory pullrod to access the 2nd slide buried in the valve cluster, but I fortunately never have to use it.
I realize this is for a differnet model Mirafone, but there is a lot of good info below. I am quoting this poster anonymous to help keep them above the fray:
I don't care how much you pay for the horn No horn plays perfectly in tune. I am saddened to think that tubist are believing that one can play the instrument without pushing and pulling slides. EVERY tuba has intonation tendencies and how those tendencies work or don't work within a specific key will determine if we are pushing and pulling. Yes, one can "lip" the horn to correct these intonation problems. BUT, what happens when you lip the horn? YOU CHANGE THE SOUND!
Now I may be going out on a limb here, but do you really want to change the sound every time there is an intonation adjustment? I would think that one would sound like three to four tubist going up and down a scale..
The tendencies that I have found with the 1291 are as follows:
C in the staff to low C should be pretty close. Provided your using the correct mouthpiece. Please use a Euro shank!
E in the staff will be Low (like all Miraphones) use 1-2 and pull
G at three bottom of the staff is a bit low, (like all Miraphones)
Eb in the staff 2nd valve is low, use 2-3
Ab at the top of the staff is a bit high use 2-3 (I have combined Eb and Ab here to show that the 3rd slide of the horn will be out about 1 inch, that's the way it is designed) This will allow the 2-3 combo to work on Eb and Ab.
Db as on ANY horn is sharp (2-4) pull on 4th slide.
Yes you can use 523 BUT all these horns are designed to play with the least amount of valves down, 523 is not as friendly in most cases.
Low Gb 2-4 is sharp., out with the 4th slide, Here is where thre 523 can be used, but I still think it changes the sound of the horn. Pull a bit more than you did on Db.
Any 1-2 combo will be high (like on any horn) pull please.
D in the staff is flat on just about any C tuba in with the first.
I'm not saying that you will NEVER lip the instrument, We all must do that to a degree, BUT if we can get closer with a slide and limit the lipping the sound does not change as much AND we miss less notes.
. I will post some pictures of my handy work. Keep in mind I had some help from my Grandpa. This is somthing he got to use his lathe for so he enjoyed it to 
.
