Definitely stick with AFT!
This ATPL has probably been the most challenging thing I have ever done!
I self studied MET and Human Factors three years ago and passed with no issues using AFT books.
I've just been to Maroochydore with AFT and did Nav, Systems, Perf & Loading and Flight Planning. Missed Nav and redoing that very soon.
Self studied Air Law with AFT book, 2 days, and passed.
Nathan's course and theory notes are spot on but you still need to put in the hard work and ensure you do all Cyber Exams.
From the course I just did Flight Planning is definitely the "killer" exam and I would recommend that if you have the time and money do Flight Planning and Performance up there. If you're cashed up do the four big ones all up there....
Nathan is just brilliant! Those that have done his course will certainly agree. He lives and breathes aviation and his knowledge is impeccable.
Cyber Exams are in the process of being/have been updated. They are just awesome preparation for the exam.
I was probably third or fourth oldest in the class. Found it tough going but enjoyable and did quite well considering.
I've had friends that self studied without the course and passed all seven in two to three months whilst working. You just have to be dedicated. Just beware that studying Flight Planning without the course will be very challenging and demanding.
Good luck with whichever way you do it.