I have a Minus K platform that I use with my turntable. It does a fantastic job of isolating and is better than most granite/wood/ platforms like HRS/SRA IMO. It is a bit fidgety initially, but you get used to it just like anything else. For example, you have to be more careful when you brush the record while it’s rotating on the table or when measuring vtf as the change in weight will bottom out the platform. However, I have not had to adjust the platform due to the different vinyl weights (180/200 gm etc). I did notice and the mfr recommends that optimal results occur when loaded near the rated capacity. I bought the 100 lb rated platform and I think with the additional marble base, the total weight comes close to, but less than 100 lbs. I think you can go over a few pounds (5 lbs?), but once it exceeds that, it'll no longer work. I also considered a Vibraplane, but having to put in air regularly turned me off. The Stacore had good reviews on WBF, but very expensive. Overall, I'm very happy w my Minus K platform – best bang for the buck. The BM-8 model that I got retails around $3k – the newer low profile platforms are close to $5k. Info at –
https://www.minusk.com/products/bm8-vibration-isolation-platforms-bench-tops-isolators.html
https://www.minusk.com/products/ct2-ultra-thin-low-height-vibration-isolation-platform.html