I am a fan of the large diameter tip for a break cue. I believe both hard leather or phenolic need to have as much surface contact with the cue ball as possible during the break. Really fat shafts are rare except for those "butterfly type" short jump cues. So....I took a jump cue shaft, heated, pulled out the quick release insert and epoxied a 5/16x14 insert. Took me 1/2 hour and it worked perfect. I use a center hit on the cue ball so I choose a fairly flat tip radius. This break cue works great and has a REALLY loud "bang" when hit. Just an idea. Again: remember it is still the form and stroke, not the cue that gives results.