It definitely can be shimmed if done well. Figure out what thickness shim you will use and put it to the far rear of the base. I would use bedding compound or epoxy under the whole length of rail. Finger tighten the screws down until touching the front at barrel or receiver and rear at shim. Let cure 24hrs or whatever recommendations bedding material says. After cure torque down the screws. You then would have a fully supported rail with built in cant. I would put release compound on the receiver and degrease the rail before bedding.
I shaved down one of those rails to clear a 10/22TD barrel. No issues arose. If you wanted that support you could bed it as well after making the clearance needed for the desired cant.
Or just buy one of the many off the shelf rails made for the 10/22 with the cant you want. Preserving that special edition Ruger rail.