Setting tonearm angle?

I got a tiny bubble level for my Akito and set it on the flat top above the cartridge and levelled it. Seems to have done the job and the cart tracks perfectly.

The implicite assumption is that cartridges are made for
the parallel position with the record. The other implicit
assumption is about the bearings position in relationship
to the record surface. Those are, uh, theoretical assumptions.
The actual state or situation always start with: 'it depends...'
But VTA has only 3 possibilities: parallel, up or down.
I would say 'depending' on the position (angle) of the stylus
in the groove and the position of the coils in the generator
which depends from the VTF.

I have been looking into this recently, perhaps you should read Michael Fremer's articles on SRA and VTA. I suppose what troubles me is that in order to change the SRA by 1 degree the tonearm (9") needs to move about 4mm, longer arms more! This would put the bearings in a very unnatural position with respect to the record surface if more than a couple of degrees is required. So I don't have an answer, like you I'm searching for the truth/a solution. Just some things to think about, especially the magnitude of adjustment required to make a meaningful change in the SRA. Going by ear is fine if your baseline is close enough, you can tune the sound! but I suspect stylus and record wear may be a factor if the angles are way out. Please let me know when you find a solution.

If you want to demonstrate or hear for yourself what a mis-aligned cartridge sounds like-get a test record. I've been working on my setup's alignment over the past couple of days and think I finally have it "dialed in". The VTA's correct, the SRA is correct as is the azimuth and the amount of anti-skate and lateral balance. Before I corrected, my setup always distorted slightly during loud inner tracks. After I was sure the cartridge was mounted correctly (having used every template, etc. available), I was able to use the test record's test tones to fine tune the lateral balance and anti skate to the point of lowest distortion.
My setup passed all of the "torture test grooves" and sounds quiet throughout playback.

01-06-13: Wolf_garcia
I got a tiny bubble level for my Akito and set it on the flat top above the cartridge and levelled it. Seems to have done the job and the cart tracks perfectly.

If you don't have a Graham Phantom Supreme which seems to be the only arm with a built in VTA bubble level, I also use a small circular spirit bubble level on the top of the cart mount like you do. It works very well on my Clearaudio Universal arm that has on the fly VTA. My bubble level weighs .5 grams so it doesn't effect VTA too much through cantilever compresion due to the added weight of the level over and above the desired tracking force.