Pani, Which version of "Nantais Lenco" do you own? I used to own one, too, and I used to follow Jean's meanderings on various websites. He was or is constantly upgrading his ideas on how to improve the base table, so his work has a temporal quality to its quality. Mine was in a massive plywood plinth (I'd guess 50 to 75 lbs total weight) with the OEM Lenco metal chassis bolted directly into the plywood to dampen it. Then I entered my "slate phase", in the early 2000s, and this led to my selling the Nantais Lenco. I found an NOS Lenco and harvested only its motor, idler wheel, and platter. I had a slate plinth cut for me and I mounted the motor on a PTP top plate, made by Peter Reinders, who is also a boon to Lenco-lovers. The PTP is bolted firmly to the slate surface. I purchased a huge bearing from a guy in England, and I had the platter spray painted with a dampening paint, plus I took a cue from Win Tinnon and further dampened the platter with O-rings straddling the circumference,. My slate slab weighs about 65 lbs. I did not try to devise a removable tonearm mount, so I use only surface mounted tonearms on the Lenco, specifically a Dynavector DV505. The piece de la resistance was the addition of a Phoenix Engineering motor controller and Roadrunner. I am not one to make definitive statements about one TT being better than another of my TTs, but this Lenco competes in every way with anything else I own.
I apologize for the question, because it is an obvious one, but in your comparisons among the tables you mention, were you using the same tonearm and cartridge in all cases, or even in some cases? Thanks.