Fling wing
There are no feathering bearings in the head, done by the strap pack. I presume you have balanced the head with no blades on ? Needs to be less than 0.1 ips.If so once the blades are on you will have to adjust the pitch links for the hover. tabs are only done in forward flight. Once the track is good then sweep the blades with the dampers to sort balance out. If the track keeps changing then you have a problem with the bushings in the scissior links. How new is the swashplate bearing, this has the same overhaul life as the head ? Droop stop rollers and plungers will make no difference. The only other thing to check is the uniball. If this is stuffed you will get a boom boom when you lower the lever from a cruise.
Bear in mind that you cannot relate the blades being in track and balance from old to new head as the heads will obviously be different.
I could always buy the d model off you and sort it !!!