Actually Jeff, I was referring to the shooting of the target with the camera to get a WB Preset, before you even get to LR. Thanks for the head's up of the resizable WB tool in LR4 though - didn't realize that! I'll have to look for it in my Beta.
Bill, I'm shooting with a D700 and if I have my 17-35 on I can't fill the frame without getting so close that the target gets out of focus. When I take the preset, the camera comes back and displays "Good", so I'm assuming it is. I guess if it's TOO out of focus I wouldn't get a Good preset.
I guess the core of my question is that how much viewfinder do you have to fill with the target to get an accurate WB reading to create an in camera WB preset. Is it the entire viewfinder, a centre spot, or does it depend on what you have your Meter set too, i.e.. spot metering?