I used a couple stools to do this accurately.

after spawning a plastic cup, Rotator was used to set the prop rotation to 0,0,0.
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=105413954

Stacker tool was used to spawn every other plastic cup.
https://steamhost.cn/steamcommunity_com/sharedfiles/filedetails/?id=264467687

the offsets in the Stacker tool options are actually the distance between the prop's bounding box. the bounding box seemed to grow and shrink depending on the prop's rotation.

Did you use the dupe gun on all of that, or an addon...
That seems surprisingly...well-made. Or maybe it was just you who spent a fuckload of time.