I have owned a variety of cues and after market shafts. In my experience, the principle impact the butt has on play is the *feel* of the hit, and the balance. The material of the joint and the pin itself can have quite an impact on balance and hit. My personal preference is a flat faced wood to wood joint with a large pin. For me I really love the feel of a G10 pin, and I guess 3/8-10 is my favorite. I have had cues with the Uni-Loc joint (which your Lucasi almost certainly has). I must say that I am not a big fan. I find that joint to feel "clanky", for lack of a better word. That being said, I took one of my cues out of retirement...a 2000 "Sneaky Sam" by Samsara. It is basically one of their early plain jane, all black cues. Not cored. It has a Uni-Loc joint. I lent the cue to a good friend of mine. She is using the 314-2 shaft I had for it. I must say that might be one of the best hitting cues I've ever tried. I simply can't believe how good it plays. However, I really think this is the exception to the rule. I currently play with an Andy Gilbert wrapless, amboynia burl handle and points on ebony. I use a 4" extension made by Mike Webb, which is basically a maple piece with a thin phenolic sleeve over it, and a G10 pin. I use an OB Classic shaft, 3/8-10 joint. I LOVE my cue so much. It is perfect for me. Now this is the part that might interest you:
When I first got my Gilbert, I had been playing with a different Samsara butt with that 314-2 shaft my friend is using now. The cue played nice for sure. When I got the Gilbert, which I bought with a 314-2 shaft that Andy put the joint in, OMG my game seriously went up. That cue played so much better...it just gave me such a clearer feel for the cue ball. The *deflection* was pretty much exactly the same. The difference was all about the hit and the feel. Plus, my cue is so gorgeous, and it didn't hurt owning something beautiful that I loved and designed myself. All those factors contributed to a better overall result for me.
So shorter answer: You may gain some benefit by trying a butt with a different kind of joint...it simply may suit your style and preferences in hit and feel. Your Lucasi butt is made with good enough quality that it should work just as well as any Predator butt. Honestly I doubt the difference in feel would be anywhere near the difference of changing joints. I would grab a 314-2 (if your thinking Predator..for me I'm VERY happy with OB, I'd do the OB Classic pro), and just put it on your Lucasi butt. The accuracy and deflection will be as good as any Predator. So yes, select your shaft based on how it plays, how much deflection you want. For LD shafts, they are generally very consistent in play from one to the next of the same brand and model. Solid wood shafts vary much more, and each one will be unique. Select the butt based on looks, feel (wrap or no, balance, joint type), and HIT (kinda the same as feel). Don't worry that you will get more or less. Generally this is NOT the case.
Hope this helps,
KMRUNOUT
Thank you for your answer so much. It brought me a light, and opened my mind for a other brands, and joints.
As you saying, I will buy for myself a LD shaft from predator. And then in future buy a butt based on how it hits, feels and looks

Thank you one more time.
But folks, I'm still busy thinking is the difference between Z-2 and 314-2 so big like it is showed (or I looking on it) ?
I asking because, today when I played, I took my break cue with 14 mm tip and I compared with my playing cue with 12.75 mm tip.
And to be honest it wasn't a huge (atleast optical) difference between them. And that is 1.25mm, while bt. Z-2 vs 314-2 is 1mm.
So is it a drastic difference in shooting, can it cost a inconvenience in game, can I miscue much more often, or it is just a matter of getting use to it ?