I hear you. I might take you up on that offer, I'll let you know.
Following:
http://www.capgo.com/Resources/Tempe.../RTDs/RTD.html
I'm calculating that a 0.01% error (0.01 ohm) translates into a temperature variation of 0.025 degrees C, for a PT100 RTD. How do you figure 3 deg C? 1% error?
I guess I was having a rough day. The answer is to pick up a few resistors at +/- 0.01%, and see how my DMMs respond to it.
What I still don't know is how I'm going to create a specific resistor. Right now, an array of 10 * 1K variable resistor looks promising, but I don't know if it'll be feasable to get to an ohm value within 0.01. Not entirely sure how I'd go about building something like this either.
I'm also missing the proper probes; I have a simple set of (single wire) probes from probemaster.com, but I need to use 4 wire probes for this. Gonna have to dig up some more info on that too.