Hi @lewm ,
Here is a bad thing about a spring-suspended DD turntable: The energy put into rotation of the platter is also going to twist the chassis on its suspension, in the direction opposite to platter rotation (counter-clockwise).
EMT had solution for this issue for "light weight models 948, 938. Look at page 5.
Model 950 had a very light patter and very heavy 70kg chassis.