If you check out Lee Valley Tools, phone number 1 800 267 8767 they sell really good solid brass screws of various sizes and styles and are excellent to deal with.
If you need help installing the cheek piece drop me a PM and I can email you step by step instuctions on how to install the cheek piece. I aquired these instructions from a fellow who is reproducing and selling the cheek pieces.
I know what you mean about being reluctant to drill into your stock, I went through the same thing but mine turned out really well by following the instructions.