Agree with all of what's been said, especially Helen's post, and the later comments about not really needing ground-school - most people should be capable of passing the PPL exams through home-study.
Regarding the Confuser - I agree that it's an excellent resource to check that you're ready to take an exam. But don't try to get away with learning from it - learn from Thom or Pratt, then do the Confuser test, then do the exam.
As for the choice between Thom and Pratt, the best thing to do is use whatever your instructor recommends. That way, if you have questions, he'll be in a good position to help you out. (Yes, you can ask your flying instructor questions about the groundschool without having to enroll on a formal groundschool course!)
Good luck, and enjoy it!
FFF
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