Hi newb here. Didn't read all the responses in this thread but believe this is a topic all P&W Teams deal with. At my church we've gone with electronic drums and adding baffles onto the walls.
Recently the P&W Team has been asked to go all acoustic (guitars anyway) to try to work out the sound pressure levels. We added subs so the FOHs won't have to be cranked so high. Seems to be working, for now.....lol.
Personally I think the volume issue lies with our P&W leader. As he gets moved in the Spirit, he starts strumming so loud it's "meet-you-at-the-end".