Pickup and chambering a "semi-acoustic"

I'm working on a custom guitar project and I need options and information. The guitar is going to be a modified copy of a Gibson Chet Atkins SST. For those of you unfamiliar with this guitar, It's a solid body acoustic electric. It's intended to eliminate feedback at higher volume, and it's extremely thin.

There are two issues I'm debating, the first is chambering the body. It's going to be a mahogany body with either a quilted maple top and back, or with a spruce top and back. I'm wondering if A- chambering the body is going to do much other than reducing weight, and B- if I do chamber it, is there some special way to determine where to put the chambers? I don't expect this guitar to be any different than an electric when it's not plugged in, ie no amp, very little sound. The second question is what pickups to use. I'd like to have it as natural sounding as possible. Obviously I'll be using a piezo, but what about either a magnetic soundhole pickup or microphonic pickup?

I really like this type of guitar, and I wish more performers would use them than dread's for live performance. A great example is the Turner Renaissance series, which basically has a bent rim design and a solid center block. I wouldn't worry much about the specifics on the chambering, and in fact you could do worse than to fill those chambers with expanding foam. Trying to "tune" the air cavities on this type of guitar won't do much for you as there's not really enough air in there to get down to the frequencies that you'd want to enhance.

As for pickups, the undersaddle piezo cable pickup types are most commonly used. You could put a magnetic pickup in the "soundhole", but I've never really been all that excited by the sounds that come from those. Your mileage may definitely vary there. I'd recommend not putting a microphone in there, as again there isn't that much air to work with. You'll definitely want an on-board preamp, which you can either buy or build using the design on the MIMF Library.

Heres one I just finished. It has a One piece Rosewood back, Maple sides, one piece Walnut top. Wood is over a hundred years old from antique shelving. The area where the neck mounts has to have a good size maple block of wood, The bridge area is optional. I put a block there for more sustain. I have one that doesnt and it sounds more acoustic. The sides are about 1~2" before routing edges. The top and back overlap the sides and glued in place. Mini Buckers sound fantastic. Went with TOM bridge cause the tops arched. (Wood was perfectly warped so I put it to use) The finish near the pickup was later touched up after installing bridge pup.

A spruce top and rosewood back and Piezo bridge and regular pups will sound great. Will need a preamp for the piezo. Allow for the room needed.

You may want to look at the Tele and Strat Acoustic electrics as well for ideas.