Polaris, Proper Motion, and Precession

Because of precession, Polaris will be most accurately "the north star" in
about 2102 Somewhat less than .4 degrees off, IIRC). Then not again for
almost 26000 years.
Anybody ever calculate how Polaris' proper motion changes things on a 26000
year scale? That is, 26000 years ago, was Polaris closer than it will be
this time? How about 26000 years in the future?
When was/will be Polaris most accurately the true North Star? (I assume that
our calculations running into millions of years either way would be
inaccurate due to perturbations caused by passing stars, so let's keep it
with 1million years either way.)