Hey Cliff..I'm a Blues Harp player..still use harp in a few songs in my Cajun/Zydeco/Country Rock/Blues band and on our CD...yep..we cover a lotta bases !!LOL

I think you're onto something, Cliff....that Cruncher would take plenty of 'grunt ' from the internally miced accordions.
Feedback is a complicated subject matter but I like where you're goin' with this [I play single row button accordion Bb and C ) and the grounding I had with diatonic harp REALLY helped me get along with the accordion.

As far as what accordion to buy...I have two Louisiana Hand Mades ( Bon Temps made by Jude Moreau and a Master by the late Mr. Charlie Ortego).
My experience is don't take short cuts..as an experienced musician you'll fast become frustrated with a unit that has weak points or low output....( there are lots of varied opinions on this subject matter ).

The Cajun units have power and precision and reliability. The other non- Cajun Louisiana units always sound to me like folk instruments for gentle souls...probably very nicely made, but...

Weltmeister..can't comment..probably a real good instrument..but for me they're all a bit lame compared to the genuine Cajun Hand Mades, for want of a better description.
Regards, Darryl, Australia.