Blackburn rack mounts are good. Often found on E-Bay. But they may not work on those Bianchi short dropouts without modification.

I've used Burley chainstay/seatstay trailer hitches as well as Avenir chainstay clamp hitches. There is some risk of paint damage.

My guess, however, is that the left clamping QR hitch you are using won't harm the retention of the wheel on the right.