The slight advantage a 12" arm has in tracking error is not worth the extra cost and hassle mounting it!
Stax Long Tonearm UA-70 Yea or Nay
I'm still looking for a long arm, how about this one?
https://www.ebay.com/i/264541464391?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=264541464391&targetid=858380238160&device=c&mktype=pla&googleloc=9003512&poi=&campaignid=6470719340&mkgroupid=77931583832&rlsatarget=pla-858380238160&abcId=1140476&merchantid=113598624&gclid=Cj0KCQiApt_xBRDxARIsAAMUMu-VJS0luvENQV8ZPP_LkAR9KF2bF4LtoEJIqhJ4H1ancAV1h8tXWlgaAvz2EALw_wcB
https://www.ebay.com/i/264541464391?chn=ps&norover=1&mkevt=1&mkrid=711-117182-37290-0&mkcid=2&itemid=264541464391&targetid=858380238160&device=c&mktype=pla&googleloc=9003512&poi=&campaignid=6470719340&mkgroupid=77931583832&rlsatarget=pla-858380238160&abcId=1140476&merchantid=113598624&gclid=Cj0KCQiApt_xBRDxARIsAAMUMu-VJS0luvENQV8ZPP_LkAR9KF2bF4LtoEJIqhJ4H1ancAV1h8tXWlgaAvz2EALw_wcB