Used the 4l80/60 Lokar rod kit on my 6L90. Picked kit with longest rod. Main difference between 6L80/90 kit and 4L80 kit is arm on transmission is offset for the 6L's. Think the 6L arm might have caused more work and it is not available with the longest rod. I heated and bent the rod a bit for extra clearance around header and transmission cooler lines. With arm on transmission at about 9:00-10:00 and pivot adjusted all the way at end of arm I hit all gears and they line up on column shift indicator. PRNDM. M lines up with the 2 after D. 1 lines up as well as the movement in transmission is there, just not used. There are some pics in post #257 of my build thread. None of the column, can add some if wanted. It is a factory tilt. The trick to getting indicator lining up is to put the arm in the position I indicated. Instructions say to position it much lower.
Kit I used
https://www.summitracing.com/parts/LOK-ACA-1811