Completely Portable Live Room Treatment

I am considering the possiblity of traveling to different churches and setting up my recording equipment in a room of the church to do on-location recording. The type of recording I would be doing would be almost exclusively vocal soloists, ensembles and small choirs (say 1 to 40 people) with the piano accompaniment either being pre-recorded, played in a different room (like the auditorium), or performed on a digital piano. The singers would wear headphones. My equipment would be set up in the room with the performers, so I could record and run the session at the same time. The projects would be mixed and mastered elsewhere. I know the whole idea probably sounds like a nightmare to some, trying to consider and plan for less than ideal recording conditions in who knows what sizes and shapes of rooms. I have done this successfully on several recordings (8) at my home church by simply lining the walls of a rather large room with six-foot plastic tables leaned at an angle (diffusion), with a few 703 panels and foam handbell table pads interspersed around the room (absorption). The room has a drop ceiling and carpeted floor. I was able to achieve a space with no flutter echo, minimum bleed between mics, a fairly nice balance between absorption and reflection, etc. The questions I have are these: 1. What should be the goal acoustically of each room I would be trying to prepare? Fairly even reverb at all frequencies? Is this something that could be accurately tested and/or altered on location? 2. What would be the best way to achieve this goal, assuming I could take along some sort of portable treatment in a large trailer? Check out the pictures and Sketchup File. Would making up a bunch of these types of John Sayers wall units work at all to help treat a random room?

How about these half size stackable units?