The old arm-specific Wallytractors are my favorite alignment protractor . Just used one this morning.
Wally Malewicz's legacy lives on...Wallytractor
Good news...WAM Engineering now making a universal version of the Wallytractor. It has the novel feature of accounting for inner groove diameter variations between older and new records, as stated on their site. Cost is $395, which seems competitive between the Mint LP and Smartractor, considering the feature set. Looking forward to the release of other products.
https://www.wallyanalog.com/
https://www.wallyanalog.com/