I am 5'7", strong for my size (workout, lift), but I am 60 now, and I bought a J&J break/jump cue about 1 1/2 years ago. (I have 2 shafts for mine).
I normally play with a 20.2 oz cue, and my J&J is a 19.5 oz..
Now, I have not broken with the BK2, but have with the BK, and my J&J breaks better than the regular BK.
I use to be strictly a separate break cue and a separate jump cue, but the J&J has changed my opinion about that. You do what you want, but if I was going to spend some bucks like you are for a BK2, I would want a Break/Jump cue, not just a Break cue.
I think the stiff conical taper to 14mm phenolic ferrule/tip is what is mostly responsible for the added power in breaking with them. I mostly got mine because I am getting older, and needed to put some 'snap' back in my breaks like when I was younger. BTW, the phenolic tip has actually helped me in form on the break, because I had to concentrate more on my breaking form to be consistent with it instead of just concentrating on power.
