Should I use Myrtlewood blocks under my Lenco 75 ?

Yes. They are inexpensive, can't hurt.
I use them under my Lencos.

Thanks oregon ,

what if I put 4 between the plate and plinth ? my plate is not yet firmly joined down

Alex,
Although the Lenco sounds better than many expensive tables just sitting on a bunch of bricks, it really needs to be mounted to a plinth for best sound. Then use spikes at three points and place place blocks under the spike points.
Shoot me an email. I'd like to see your Lenco/plinth.

i agree need to be mounted on a solid heavy plinthe like MTHE MASTER JEAN NANTAIS IS DOING FOR ALL LENCOS , GARRARDS