Tuning the instruments of Hell to something more suited for the Symphony has proven to be difficult but rewarding work. I now offer general descriptions of the problems involved in tuning each Band, plus helpful suggestions for each one. I am avoiding mentioning the problems encountered with tuning to specific Archangels. They are better able to describe the challenges than myself.
Balseraphs: Ah, the sound of a Balseraph when it is played as a Seraphim for the first time is more joyful than I can describe. Tuning one is actually a simple matter. As they tend to be set for lower notes than Seraphim, it's a matter of removing the strings, keeping the neck tension constant, then adding strings that are set an octave higher. Make sure about the sound; many Balseraphs are horribly out of tune and refuse to acknowledge this. You will note that the wood goes from dark grain to lighter once the work is done. Don't worry; this is perfectly normal and will not affect performance.
Djinn: Recalibrating these brasses and woodwinds is about as easy as Balseraphs. It's usually a matter of a new reed and cleaning out the insides. If you're fortunate enough to have a Djinn that is meticulously clean, this will make things easier. Like the Balseraphs, you need to check the sound on it while you fix it; Djinn are typically set for minors that make it sound depressing. When you can do a perfect scale that doesn't sound mournful, you know you're set.
Calabim: The destructive natures of these instruments means that you need to have your workshop cleared of all other instruments when you are ready to work. The boundless energy of an Ofanite is directed inward with these, so they tend to lash out unpredictably. Give it something to attack while you work such as cinderblocks or a metal wall and you should be fine. Once it has been tuned, make sure you have an open door ready; they tend to be quite energetic.
Habbalah: This is one of the most difficult instruments to tune. It can go from sharps to flats without any warning and all the while they insist that they are set to Heavenly standards. Usually, you have to play it and tune it at the same time; force it to go lower or higher as you work. For the designs found on the flesh, you will need a fine grit sandpaper to gently work those out. Once work is completed, test it out by getting into a debate that could easily become inflammatory. If it can keep a middle C in the face of all of that, they are ready to be released to their new Superior.
Lilim: The Lilim are the most difficult to work with since Heaven doesn't really have schematics on them. They also rarely agree to join the Symphony and each one is unique. Get the help of a trained professional before beginning work. The first problem is to figure out which type of instrument they are (Woodwinds, Brass, Percussion, Keyboards, other). Use that as a general frame of reference. The Geases are the trickiest part since they can undo the work you have done. You can find the demons that hold them and point out that it's in their best interest to spend the Geas in a good way (Mark and Michael's people are the best ones to handle this), or you can remove them in the shop. If you choose to remove them, there will be flaws in the instrument no matter how careful you are. This won't hinder playing, but it will affect the appearance. Use your judgment.
Shedim: Coveralls and gloves are the best way to start work. They are slick and polluted and I still can't understand how they are so effective as instruments. Keep in mind that they don't really fall under any category. This makes it quite the challenge for the inexperienced craftsman. Your best bet is to get a Kyriotate as an assistant, preferably one who has been through the tuning procedure. They are not only able to guide you along, they can calm the Shedite down and help it as it begins to get reshaped.
Impudites: Their vocals are good, but the coarseness of their training is apparent when you begin work. A strong coach that is able to get them to see the flaws in their voices and provide honest feedback is the best help you can have. Make sure they come in periodically for minor adjustments for the first six months. After that, they tend to not wander off-key.