Make sure the arm and cartridge mounting hardware is not loose at all. The loose hardware can give you some resonant distortion that will have you adjusting tracking force and antiskate for hours. I doubt that would be the whole problem but it can contribute. This going to seem like a dumb question but are the records clean ? Also, when you are making your adjustment try not to do it on an album that has 6+ cuts on each side, greatest hits albums and compilations are generally a little more compressed. If those are the types of albums you listen to often disregard that. As far as the vta goes I'm using a reference sonata and I seem to get the best results with the arm just below parallel to the platter so the cartridge is tipped slightly back. I track at best around 1.75g.
Regards, Bill
Regards, Bill