I've used a hollowbody for the last seven years playing guitar, two years with a seth lover bridge. There are a couple of key things to controlling feedback with a hollowbody:
1. Be very careful about your positioning from the amp . . . try not to ever stand directly infront of your amp! Always go off to the side a bit or behind it if you can. This is the simplest and best way to stop your guitar from feeding back.
2. Turn down the gain that you're using, even if only a bit. Semi-hollows can't handle EXTREME metal distortion (although you should be able to get some heavy hard rock tones from them)
3. If you're not playing your guitar, use your volume knob to turn off your pickups. This prevents that screetching you hear when you go to grab your beer and your guitar goes crazy

4. When you're soloing, try to mute the strings that you're not actually playing. This is kinda tough to do at first, but eventually you'll get the hang of it.
If you follow all of these, you shouldn't have any problems whatsoever with feedback at full gig volumes. At least I havn't . . . anyone else have comments?