Touring - Best Seat Post Rack suggestions

Argh...
it appears as tho my dream of mounting a smallish NItto rear rack has hit a snag:
I smacked my head and looked down and realized...ACHT! Carbon Fiber seat stays (bike has not rear or fore rack braze-ons). Looks like cinching a Nitto seat stay clamp to fasten the rack on with might be a Bad idea on the CF (BLEAH)

I am taking order of a large Carradice saddle bag, but I'd still like a rack down the road to haul the miscellaneous commuter items, my rack trunk, or support the saddle bag (otherwise it's a Carradice bagman or QR bracket)

Can anyone chime in with their reviews/recommendations on seat post racks?
I'v heard this and that (they swing around, they loosen, the welds bust after 3 months)
Has anyone got one that has seen some use, light touring, etc. with success?

Thanks!!!

I choose to question your assumption about the appropriateness of attaching a small rack to carbon fiber seat stays. If I were in your shoes, I'd consider attaching a rack with P-clamps. I'd use either an old inner tube or some kind of plastic/rubber layer between the clamp and the carbon fiber. What needs to be avoided is creating a stress fracture in the carbon, for instance if a metal clamp is wearing directly on the stays. You've already enumerated the problems with seatpost racks.

Attach a clamp onto the lower part of your seatpost and bolt your rack struts onto that clamp. A small diameter seatpost clamp should work. I thought of doing that myself once.
Another idea is to somehow attach the rack strut(s) to the brake bridge.
There are several other creative ways of securing the struts depending on the rear geometry.

What bike is it for?