Z AXIS Adjustment design Help

I'm getting between 0.2mm on the Y side and 0.33mm on the X side over around 130mm of Z axis travel. I've got it down to this from rather excessive amounts using shims but I'd like to get it even better as my surface finish when facing Ali is leaving a burr. Ideally I'd like to see some of your designs on how you make your Z axis adjustable to tram it. I've currently got a bearing and then a pin on the rear of the plate that allows the spindle housing to rotate around when I turn a bolt to then get it trammed in one direction but it's not amazingly accurate.

I've got a image here of roughly my current situation. I built this over 2 years ago with a ML-7R and a pillar drill so I got it fairly accurate but never really could manage those fine tolerances over such distance.
Attachment 25647

Rob