I'm not in DT's league but here's my answer:

20 - too tight to shoot at same spot without messing up arrows
30 - sometimes touching but most groups are "scattered" in a 3-4" circle
40 -at this distance and beyond I can aim at same spotwithout a BIG fear ofbreaking anock or tearing a vane off. Groups areinside 4-5" circle
50 -last week I shot a 3 shot group in a3" circle, but mostof timeit's more like 6"
60 -at thisdistance my goal is to4-5 arrows in a 6" circle but more times than not Igetone or two that are1-2" outside.
70 and 80 - no pins for these distances, I use mybubble, but I'mnot accuratethis far out

BTW, I seem tobe more accurate on a 3d target than on my Rhinehart ball b/c I can see better, I guess that's how most guys are