DaVinci tonearm and azymuth

Placing a shim between collar of armbase and armboard will create problems - and won't solve any. Correct azimuth is a must and is determined by the position of the stylus in the groove and towards both walls. Thus a headshell level (spirit bubble or not....) has little to no use as Dougdeacon and Essentialaudio already mentioned correctly.
The problem has to be fixed at the source - you can not "correct" a misalignment of azimuth anywhere else in the chain - only at the stylus.
If the stylus is not 100% vertical in relation to the upper plane of the mounting cartridge body, you need a headshell which can be rotated in its axis - at least to some degree.

Its an imperfect world - thus we need alignments....

Rsrex,
Good idea. Of course the optimal SRA for one 120g record is not necessarily the same as for the next, especially if it's on a different label. Ultimately each LP must have SRA individually fine tuned by ear. Still, starting from the same baseline for a given thickness should shorten the process - and of course you knew THAT. :-)

As for the Freickert-software... it implies for correct function in azimuth-adjustment mode, that both coils of a given cartridge do have 100% identical output.
If this is not the case - which you can count on in 99,99999 % of all cartridges - it will help you little to adjust azimuth. As it compares output of both channels to give identical readings.
You need to know the exact output of each coil before using this tool.
Hard to get......
Sorry folks - azimuth-adjustment in real world conditions has to be (and can only be ..) done by the one single instrument most audiophiles seems do trust the very least.
The ear........

Hi Doug,
if the arm-post is tilted relative to the platter (not 90 deg.), the azimuth keeps on changing from beginning to the end of the record, aye.
Why? Because the bearing (most usually has a ~ 20 deg. off-set relative to the straight axis of the arm). One thing I learned real fast when using some cheap arm (Pro-Ject 9c) with a sloppy arm collar for setting VTA.
Go figure... and Dertonarm should concede being in touch those Egyptian geometrists :-)
Axel

If the stylus is not 100% vertical in relation to the upper plane of the mounting cartridge body, you need a headshell which can be rotated in its axis - at least to some degree.

Or shim between the cartridge and headshell. I do that where azimuth adjustment is not available. A fraction of a degree can make all the difference.