It might be better just to buy 1% parts. When I made thermistors (a long time ago) they were sorted by a binning process. All the tested parts that fell within a 1% tolerance, for example, were binned as 1% parts. Those that fell outside the 1% tolerance were tested for 5% tolerance. Those that fell outside the 5% tolerance were binned as 10% parts. You might have a hard time finding a 1% part in a bag of 10% parts.
Also, NTC thermistors have a non-linear RT curve which will affect on your sub one degree accuracy requirement.