12mm
I have all the shafts from custom cues that I've used "pro tapered" and reduced from 13mm to 12mm... I like a longer bridge and have big hands so on a closed bridge I like the feel of 12mm for about 12 inches from the ferrule back, also from what I am told..on non LD regular maple shafts, a 12mm will deflect less then a larger size.
I've noticed that most custom cues come with 13mm or larger shafts. Some of these shafts are quite "meaty" as well. Do you use the original shafts the way they are, or do you have one or more of them retapered? Perhaps you use aftermarket shafts (ld)?
The reason why I ask is that I recently purchased a custom cue (that I do not want to name at this time) and the shaft is very thick and heavy. It weighs about 4,5 ounces. While the cue makes a wonderful sound and feels very solid, the thick shaft and and taper makes the cue deflect quite a bit and I also feel like I sometimes get less action on the ball with this shaft than even cheap production cue shafts.
It seems that many people don't care much about deflection at all, but what about the action on the cueball? Yes, yes I know you are supposed to get good action even with this kind of shaft, but I find more difficult than with "whippier" shafts. It just seems like the shaft won't help you at all. If you hit the ball even slightly bad with this shaft you get no action at all on the cueball, while a similar stroke with a different shaft will get you enough action to get the job done. I am kind of frustrated right now, but I don't want to chuck out or retaper the shaft just yet.
I have all the shafts from custom cues that I've used "pro tapered" and reduced from 13mm to 12mm... I like a longer bridge and have big hands so on a closed bridge I like the feel of 12mm for about 12 inches from the ferrule back, also from what I am told..on non LD regular maple shafts, a 12mm will deflect less then a larger size.