Checking azimuth with a DMM or scope, please advise

My advice: use the LP headshell for its azimuth adjustability.  Forget high priced measuring devices.  Your ears should be enough.  Trust them.  Azimuth adjustment is easy to hear, though better in the long run if you had purchased a TT with arm easier to adjust for azimuth. So with yours it will take a few tries, but you'll get it.  Begin with headshell parallel, from front, to its reflection in the record.

For some reason I'm having a hard time quoting so forgive me.

I ran the HiFi News Test LP on my last Denon 301 mk2 ans worked good. This time around I'm using the AT33PTG/2, along with a Cardas rewire, tonearm and unbalanced leads.

I have the cart pretty much aligned, but not 100%. I will say these last upgrades have completely transformed this table. Imaging, clarity, air or spaciousness in regards to instrument decay and vocals is quite remarkable from where it was.

I guess I'm just after that last bit of adjustment accuracy if the electronics can offer that over my ears.

I agree a good pair of headphones while making adjustments are fairly accurate, as the end result will be ultimately how it sounds.

I have used electronic devices to adjust azimuth, but they simply don't work as well as my ears. Invest in a good torque screwdriver, though. YMMV

This little doo-dad seems to work pretty well:   https://www.ebay.com/itm/253375545273