It's sometimes a hit or miss playing an amplified ABG indoors. I've done gigs with no problem and three weeks later in the same venue, it's like a banshee has moved in. Sometimes, the banshee appears in the middle of a song and never returns?
I play an Ovation Elite V and always use multiple plugs - the bass has about a million sound-holes of differing sizes and to be honest, I'm not too sure they make all that much difference in the end.
Anyhow, best of luck in your quest.