Simon yorke tone arm

I think I'm going to buy the Uni-Protractor allignement tool, which is for sale here on Audiogon.

The first half of any record sounds fabulous but as the stylus reaches the middle sound quality degrades

Hi Altoman, Which adjustments did you start with?
My ear is not experienced enough to know if there are improvements as I have just changed my cartdridge..!
What should I do to get the best out of my SY?

However the sound is already so much better since I have attempted to set up using the Uni-Protractor... Which by the way is beautifully manufactured