With a low deflection shaft you should see your english shots improve even with a thicker tip. Just remember to chaulk up
As far as the Ikon to the SE sticks. Personally I prefer the SE sticks, but they can be expensive. A lot of it depends on what you are wanting to spend. The currently SE stick Predator is selling was designed by Mezz. I believe the retail of it is 1995, but usually you can find dealers selling it at about 15% off. Sometimes more depending on dealers. Predator is pretty strict on what it will allow their dealers to sell cues for.
As the earlier poster said in the Ikon, and P3 line they are all probably going to feel about the same. Doesn't matter if it is an Ikon 9 or Ikon 5. You are just mainly paying more for the design of the stick. I am not one to speak as I have expensive taste, and tend to spend money when I dont need to on pool cues.
If it were me buying one I would get a SE. Only problem is they only sale one at a time and they switch them out about every 6 months. The current one out there now was just changed about a month ago so it is fairly new. The Lancea 1 / 2 are still fairly easy to find, and sometimes you can find older ones, but in most cases are used.
The only thing with the SE is keep in mind the person who designed them. They are all made different. Of the two I have I prefer the one made by Jacoby. I just LOVE that stick. In fact I am trying to sell the one I just got a few weeks ago but mostly because I need to do some home repairs. Its good to, and plays a lot better than the P2 I used to have.
I wouldn't say that the Z2 is the way to go. Like I said earlier the 314-2 in my opinion has a better feel to the hit. You will tell a HUGE difference with both. That being said everyone has a different opinion about them. If you like a thiner wood on the shaft then the Z2 might be best for you.
I have been reading lately on here about people's opinions on different low defliction shafts and a bunch of people prefer the OB shafts over the Predator. I personaly and curious to try the Jacoby Hybrid Edge. I haven't tried any of those yet, but I have heard good things about both. In my area most people seem to use Predator 314-2.
If you are wanting a Predator I would get what you can aford. If money isn't an option then yeah get a SE. If you are wanting to save some them get whatever Ikon you like the look of best. They are all going to play the same.
Now as for the jump stick. I recently got a Lomax jump (he is a custom maker out of GA). I had never heard of him until I signed up on this site a couple of months ago. Lots of people rage about how awesome his jump cues are. I took a chance and called him up and bought one. It is awesome. I have never been a good jumped and in fact had trouble with consistancy of just making a good hit. With this jump cue and a few youtube videos I learned how to jump with ease. I had a Lucasi jump/break cue, and in my opinion the combo sticks are harder to learn how to jump with. I sold it, and thats when I bought my predator break stick, and Lomax jump. LOVE both of them. Wont trade them for anything.
When I was doing my research on hear about jump cues I was originaly looking for a predator jump cue. They used to make one but retired it a couple of years ago. I wrote them asking about them, and they wrote me back said that they were working on one, and hoped to have it out in production later this summer. So if you are wanting to stay true to the predator line they should have it out soon.
Since you have been playing a couple of years. You might want to look into geting a break stick. Its totally up to what you feel comfortable with, but I like having the consistancy of shooting with the same sticks.