for high gain amps sir i believe semi-hollow / hollowbody guitars are really prone to feedback because the way they are built. even if you don't have a high gain amp but let's say you use high gain pedals you still get the feedback. as from sir nineworkz of the band EVEN, he uses a jazzbox as well and he uses noisegates. Pre Gating and Post Gating hope it helps.
Ay sir, kokocrunch, korek ka dyan ..yah kita ko nga yun one time, nung live performance ng Even Band astig!, sir nineworkz pala yun, hehehe!
and i'll take note of your advice too, have the same dilemma din, Now I know,hehehe