Select a reading rate of 100,000 readings per second for maximal test throughput. Of the 2, one has one handle on one side, one has two handles. 2.2 ppm for 24 hours in Ohms. 0.6 ppm for 24 hours in dc Volts.
This DMM was designed by the same generation of engineers that put people on the moon, but contrary to the moon program it is still relevant (and selling by HP/Agilent/Keysight) today. You get true 8.5+ digits of resolution at affordable price.
My only note - remember about 4 hours warm-up, do daily self-calibration if you want to stay within 4/8ppm DC accuracy