hobkirk, are you using aero levers? I'm assuming you are. If not, they make a huge difference. As for the machining of the new rims, I'm not aware of any difference that would affect braking. IMHO, you have not maximized your brakes if you are experiencing shuddering. If you want to stay vintage, I'd work on the brakes myself and try readjusting them. Also, I'd forget what the mechanic said and for $10, buy some new pads, at least for the front and try the brakes again. While I had them apart, I'd check the cable for ease of operation. I'm always amazed at how cables can screw up an operation.