Just did a quick check with the DE-5000 measuring a 53mm length of solid #12 Cu wire, this should be ~41.7nH per calculations and we measured 43nH (100KHz) with TL-21 fixture. For ACR we get 0.002 ohms tho, and this is calculated as 281u ohms, with DMM6500 we get 271.7u ohms, so obviously below the DE-5000 resolution.
Also measured a 17.5 turn open wire inductor at 292nH (100KHz) with DE-5000 & TL-21, TH2830 with 292.737nH and IM3536 with 292.17nH.
BTW the core DE-5000 is a 4 wire Kelvin Type System, the TL-21 Fixture brings the each 2 Force/Sense wire sets to the Bottom of each Alligator Clip as shown below with the 2 wire inductors. This is a left over from a TL-21 we modified some time ago for a true Kelvin setup with long Kelvin leads and clips.
Anyway, just some measurement and hope this helps.
Best,