You shouldn't use p-clips or clamps with carbon. You choices are:
Seatpost clamp rack
QR skewer-mounted rack
Carradice saddlebag.
You can get upper seatstay-eyelets incorportaed into a seatpost clamp.
You can also fit a bar bag and a frame bag.
You will have to travel ultralight but it is quite do-able, esp in summer.