AT-LP120 have similar tonearm like technics but it is not same as Technics tonearm. Technics have pivot to spindle 215mm, AT-LP120 have 214.15mm Pivot to spindle distance.
For that reason Technics protractor is not adequate to adjust AT-LP120. Sound with Technics protratcor is way better then Stevenson protractor from Audio Technica but tonearm does not exactly align with them.
Audio Technica AT-LP120 USB modded(AT440MLb cartridge),Technics SL-PS770D CD Player,Pioneer CT-S740S Tape Deck,Onkyo HT-R508 Receiver,Mod. Opera Mezza with passive radiator,DALI Trio sub moded with int. amp,HECO center speaker,BOSE surround speker,MDR-DS6500 headphones,M8S media player,DM-800HDse/CS