I used my friends jacoby yesterday.....jumped right out of a safe and nearly banked the 8 right in. That sealed the deal for getting one. Im looking at the pechauer. What is the most common size, its available in 12.5, 12.75, and 13.
For Jumping you want the fatter shaft.
A friend who is cue maker made me a shaft from a $50 break cue that jumps almost as good as the Propel and it breaks
great also. He had to drill out the 5/16 thread a little but when he did, it fit the Pechauer Jump Break and is awesome.