I've never personally tried the "Shinka" system, but in my opinion, one of the problems most people run into with binaural beats is the creators of the systems push the limits lower than your brain can handle, at least at first. Many of them push you to as low in the Delta range as possible. (1-2hz) I've found that a much more pleasurable experience is had in the 7-8 hz range. Then after you've done that for a while if you're so inclined, try the lower brainwave states.
Even better, use a combination of binaural beats with more traditional methods such as breathing and focus for even a better experience.