ateal OP" ...with regards to the suspension tuning / balancing is there
anything other than ensuring the distance between the plinth and the
underside of the suspension housing on each pillar is equal to the "B"
point of the suspension gauge (21mm). And also making sure the correct
spring is used in each location.
Is there a further check that needs to be done."
Yes. When excited - tap on the platter vertically - the platter assembly should vibrate in a purely vertical, pistonic manner, with no wobbling from side-to-side. If it wobbles, either the tower heights are not properly adjusted, and/or one or more springs must be twisted (without changing height) so that the ends of the coil of each of the three springs share the same orientation.
Is there a further check that needs to be done."
Yes. When excited - tap on the platter vertically - the platter assembly should vibrate in a purely vertical, pistonic manner, with no wobbling from side-to-side. If it wobbles, either the tower heights are not properly adjusted, and/or one or more springs must be twisted (without changing height) so that the ends of the coil of each of the three springs share the same orientation.