About the only instruments you are going to use frequently are your stringed and your percussion. During fights, while soloing, you are going to use weapons. You can still use and twist songs. They just won't be as effective as when you have the weapon equipped. Some songs dont need instruments anyway. At level 14 I was twisting hymn of restoration, jonathan's whistling warsong, chant of battle. I kept a weapon in my main and a shield in my off hand. When I hit 17 I put a weapon in both hands. If I got in over my head I would swap out the weapons for my drum and kick in selo's accelerando. Twisting that with hymn of restoration while running allowed my to heal while not getting hit. When HP was high enough I would swap back to weapons and reengage my target.

Once you get Denons Disruptive Dischord you can try an instrument twist. I found it made little difference in my damage output. Load up your loot and start chords of dissonance. When the first pulse of that hits switch your lute for a horn and play Denons. When the first pulse of that hits change back to the lute. Play hymn of restoration (you need to heal yourself). Then start CoD, horn,DDD,lute,HoR, back to CoD, etc.