Not to be a jerk (as always said before a jerky comment) but, can you play quieter when you want it quieter? Some sax players can do that pretty well. I guess you want to be able to play the bass parts hard so they are solid, etc?
Another cheap and easy - use you clip un for all normal playing and walk up to the "solo" stand mic and rip into that for your solos - this mic can even be narrower in freq. range, i.e. sm57 (cheap too) and that will layer with your normal nice sound and add more volume and a bit of subtle grit.
If this is church gig (every week, right?) the sound guy should be able to get used to pushing you for solos, I do it all the time in my sound gig when players take solos and they don't get sufficiently LOUDER (most do, and also make cool faces, stances)
_ A