Turntable isolation...

I use a Minus K and love it under my Brinkmann Oasis. I used to have a second one under a Clearaudio. You have to weight them to their limit, though, to get best results, and balancing your TT on them can be a little challenging. I use heavy brass discs to distribute the weight. Also, they seem to work better if you put a shelf or platform on top of the top plate--I use a Adona multi-element shelf.

I think a new Vibraplane is $2,000 to $2,500. It is very effective. You should call Sounds of Silence. Steve Klein is a good guy to deal with. I also looked at minus K, but per the note above from wrm57 I decided I did not want to deal with the balancing. The Vibraplane is easy to use and I check the leveling about once a month. It takes about 5 minutes. There is a guy on What's Best Forum that uses a Herzan. They are expensive.

Can you elucidate the set-up of the Vibraplane please? 

It's ok I've just read the pdf.

I use extremely low spring rate steel springs for isolating very light things like portable CD players. I use 4 cryo’d high carbon steel springs with medium spring rate for isolating most moderate to lightweight things up to about 40 lb. For heavier things up to say 80 lb I just add another spring for every 10 lb. For really heavy things like big amps and big VPI and Verdier turntables I use Super Stiff Springs, 4 of these babies will isolate things in the range of say 75 lb and 150 lb. For even heavier things add another Super Stiff Spring for every 50 lb. Super Stiff Springs will come cryo’d in the near future. And since these springs are low profile they have excellent lateral support/stability. The reason you have to load the Vibraplane in some cases and the Minus K is because there is a design load based on the spring rate of the device, so to get the lowest possible resonant frequency of the iso device you obviously want to use design load, which is most likely near max load for the design. Air springs have rated max pressure for example.