Okay, I did some balancing/measuring with my 31" Jacoby butt, my Larry Vigus 30" butt, and my Willie Speed 60" cue. Just for sh*ts and giggles, I measured my 60" Vigus break cue.. I balanced the two butts with three shafts: a standard maple 29" shaft, a 29" Predator 314, and an 30" OB Classic. I measured from the balance point to the end of the buttsleeve, not the end of the rubber bumper. Here are the facts:
Jacoby 31" butt:
29" standard shaft = balance point @ 20 1/2"
29" Predator 314 = balance point @ 20 3/8"
30" OB Classic = balance point @ 21 1/2"
Larry Vigus 30" butt:
29" standard shaft = balance point @ 20 5/8"
29" Predator 314 = balance point @ 20 1/4"
30" OB Classic = balance point @ 21"
Willie Speed 60" cue (30/30 split)
12.4mm standard shaft = balance point @ 18 3/4"
Larry Vigus 60" break cue (30/30 split)
Lyptus shaft = balance point @ 19 7/8"
I don't know if any of this is meaningful to the OP, but there is the only data I can contribute. The only thing I got out of my effort was to determine (imo, of course) that using a longer butt with a standard length shaft does not alter the balance point to any noticeable difference.
Maniac