All, thanks for the measurement suggestions and also the link to the Keson tape.
I spent the morning doing a bit more research and ended up on the NIST: https://www.nist.gov/how-do-yo...ape-measure-accurate
It's my understanding that the Tape manufacturers regularly certify their production against the NIST. The page above has a link to the NIST Handbook 44 which indicates that a metal tape between 81 and 100 feet that is used for commerce (buying and selling goods) should have a tolerance of 1/4inch. Assuming your tape is off by 1/4 inch for each 100 feet, a 1000 ft calibration course could be off by 2.5 inches. That's 13.2 inches per mile or 81.84 inches for a 10K --- or 2.08 meters of potential error.
Regarding tape temperature, the USATF course measurement manual says you should use a non-contact thermometer and measure the actual tape temperature. The interesting thing here is that a 12F increase in temperature from 68F to 80F results in only a .9 inch correction on a 1000ft calibration course. Ignoring that would result in less error than is possible from an inaccurate tape.
Of course, the specific tape you buy may not be 1/4 inch off. It could be exactly as stated or some number between zero and 1/4 inch which would result in a potential error less that 2.08 meters.
At any rate, I appreciate the input! This is a fun and certainly interesting topic and I'm looking forward to starting to measure.
My best, Tim