We have and use the typical SMD fixtures for our lab grade LCR meters, and these work well for most SMD devices except the larger types. Typical large value SMD inductors, Tantalum SMD capacitors and large Polymer & Electrolytic SMD capacitors have been difficult to measure with these fixtures, and we've had to resort to handheld Kelvin Clips which isn't their intended use as they are for leaded devices not SMD devices.
Awhile back we developed a DIY SMD fixture for our Tek 577, shown here.
https://www.eevblog.com/forum/projects/smd-test-fixture-for-the-tektronix-576-curve-tracer/This was based upon using the Lever Arm Clamp devices intended for clamping and holding down items. It worked so well we decided to try these Lever Arms for a custom DIY LCR Meter fixture and created a few custom PCBs to give this a try.
It works treat!! We tested a few SMD components that we couldn't test at all with the conventional LCR SMD Fixtures, and we did a couple devices we could test with the conventional LCR SMD Fixture for comparison. The comparison results were very good and we now have a fixture we can rely on for larger SMD devices!!
The first PCB uses both sides with different SMD DUT connection patterns, one for larger contact areas and one for smaller. We added the two Lever Arm assemblies, one on each side. You simply flip over the fixture to use the other side, and maybe do another Short/Open Calibration, altho we've found this isn't necessary unless one is interested in very low or very high impedances.
Also have another type PCB which employs a split SMD contact area which brings the Kelvin connections right up to the SMD DUT and even uses the SMD DUT to make the Kelvin Force and Sense connections, which we'll give a try later when time permits.
Anyway, hope some folks find this interesting and useful, certainly works for us!!
Best,