I think the CTX should be taken in bite sized pieces. Learn what the common coins and jewelry respond like on the screen. Then plug in the CTX to your computer and play with the Xchange2 software. Get used to loading, designing, and saving patterns and modes. Once you've loaded your own program and used it - the machine will make better sense. The last step is to read CTX related posts ... apply what you learn to what you've experienced at the park.
No doubt people probably hope their next detector (especially the expensive ones) are going to somehow differentiate junk and iron from good targets. But the first time out they realize it's the same old story, you've got to dig most targets to be sure. The TID on the CTX is second to none, but it isn't going to tell you a nickel from a pull-tab or jewelry from junk. There are iron targets that jump about and produce varied tones - it just isn't easy to ID targets with any detector.
So, take your time - read, practice, and read some more (then practice some more). Don't give up - if you aren't comfortable with the detector after giving it a fair shake (say after about 200 hours), then by all means sell it and try another. You aren't married to the thing. It's just a tool, like a very expensive hammer.
You should also know that most everybody must go through tough times and experience failures to achieve anything great (which applies to learning a detector as much as anything else in life). There will be many times you'll want to chuck the detector and give up - but the winners are the ones that keep on coming back.
Jackalope