Hi Dylan,
I'm curious how live performers like Jerry Garcia and Norah Jones and others avoid feedback with Starfire IIIs? Do they mod them in some way or do they just have to avoid certain areas in front of their amps?
Dylan pretty much covered it, but i'll chime in as I've never really understood the general disdain fully hollow guitars get that surrounds feedback. My take is that the dudes complaining about are guys trying to play a Starfire III or Casino through a cranked Marshall stack, trying to get the same sound they'd get out of a tele, strat, or 335 and frustrated that it won't do "their thing" that they're used to. Hollowbody feedback is an awesome thing and manipulating it is fun and a way to mess around with to live performance dynamics. If you're playing with overdrive/fuzz/distortion at a show through a hollowbody and upset about potential feedback, get a different guitar.
I've got a '62 Starfire III that I've played live a number of times and generally haven't had issues with feedback, if anything it's more prone to feedback in small spaces with loud volumes, ie. rehearsal spaces where you're packed in with a 4 piece band and everything is bouncing off the walls. Through a cranked champ, or a fairly turned up Princeton Reverb I haven't really had issues. Through my Super Reverb in my room, it'll feedback pretty quickly if I'm too close and turned towards the amp.
Tip one: get a band that knows how to play quiet if you're in a confined space. With the right players in a small space this shouldn't be an issue. Dynamics are your friend.
Tip two: monitor your guitar signal directly from your amp, pointed at you from side stage. If really necessary, depending on the setup, monitor everything else through a monitor pointed at your fretting hand/guitar neck and not the body of the guitar. Stage monitors pointed at your guitar will increase potential for feedback due to resonance so keeping your monitoring to just your amp or pointed away from the hollow guitar will help that (same applies to acoustic guitars).
Tip three: embrace the feedback at loud volumes - just know how to manipulate based on where you are standing in relation to your amp.
Tip four: use less distortion....not everything needs to be through a dimed tweed amp or a twin reverb with a cranked fuzz face in front of it, your hearing will thank you down the line
It's easier for me to say because I'm mostly playing clean psychedelic fingerstyle stuff, with the occasionally noisy sections using an overdrive or a distortion for added effect, all swirled up with delay and reverb. Those feedback moments mixed in with all that are just another tool in your pallet for live use, but I suppose this is all depending on what kind of music you're playing.
And if you're really still worried about it, buy something like this:
https://reverb.com/item/4793398-guild-1959-ce-100-dougs-plugs-f-hole-feedback-control