I did the CTC tests just over three years ago now and used said software to prepare. I'm afraid I can't remember any specifics but I can say that they were both certainly useful and I passed the aptitudes with a high score.
Once again I can't remember specific levels required but you can never be too prepared so just keep practicing until you reach your plateau and I'm sure you will be absolutely fine; it didn't seem to me like an especially high score was required. Also, I don't believe candidates are ranked based upon their scores, I think the tests are simply hurdles which must be crossed.
*** I actually just had a go on on Moving Cross III ( on Most Difficult) for you and got a score of 249. I passed the RAF aptitudes and CTC with high scores so if you can achieve anything in that area I would have thought you would be fine (unless my aptitude has plummeted over the last few years ) ***