@ledoux1238 thanks for your words.
i have had some advice from a very experienced la platine user on WBF (@mtemur) and so things may change. also i am currently ill and this affects my hearing. it is just cold so a day or 2 and it will be fine but this could have impacted what i perceived recently.
in any case to respond to your queries.
1. i have removed the footers i was using. i had CMS speaker footers under it. it sounded extraordinarily measured with footers. polite. formal. stiff. no fun. i accept other footers might be a better choice. i used the CMS speaker footers because they easily adjust up and down being leveraged. and they sound great with speakers. i think their maker wouldn't endorse the way i've used them here. my sense was that when i first played the la platine as i received it from germany and the previous owner with a fr64s and modified denon 103 cart and no tweaks or oil, that it sounded quite sublime. i'm not sure anything i've done since then has helped.
2. viscose thread. have used waxed floss. have used a thicker "yarn". have used my tt3 belt as well. everything sounds like what it is. so the tt3 belt which is rubberish and flat and wide made the verdier sound alot like the tt3 to my ears (which as i noted at start may not be at their best), i.e sort of thick and unrelenting like its made of plastic. viscose thread sounds best late at night (2 am) when the power is clean. music hangs in the air. one can hear very much the timing characteristics of different belts. tight rubber one had great drive with a certain elasticity. with thread i can hear it slowing down as it plays. this adds to a certain appeal i think but mainly late at night. opposite of garrard 401 thunder. waxed floss was good but seemed to heat and then disintegrate a bit. less romance with floss (could hear its relatively stiffness). i think i can hear the viscose thread stretch too. i do find it needs to be somewhat tight the viscose thread for me to make speed. the floss on the other hand could be almost falling off. i want to try silk. but mtemur recommends transrotor belt. i have ordered that. i have also ordered EPDM based belts as per a recommendation by another chap on here. i have bought the gold note deluxe (EPDM) and epdm o-rings from ebay. we will see what we get. mtemur says he has speed variation down to one quarter of what i am achieving (i am 0.2 rpm variation at best).
3. re: motor i may be using wrong terms as i barely know what i am doing. i opened motor and snipped tx output and connected my LPS 12V DC output to the wires. so i still get to change my speed the normal way etc. this did reduce my speed variation. the sound is good to me, i think i can hear the improvement. but it is less romantic somehow and i wonder if this isn't the same sort of change i got from footers. that is, more hifi, but not actually better. my touchstone is linda ronstadt when i first fired up the la platine. it shocked me how much resolution i could hear but also how much delicate flesh there was on her voice.
re: turntables right now i am wondering if i should keep either the tt3 or 401. the tt3 is very set and forget. the 401 is, like the la platine, a tinkerers paradise. the 401 is more stable than the tt3. the tt3 is more engaging and beguiling than the 401. the 401 is monumental when on song. but having everything carved out in marble for you can get tedious.