6 hours a day? If you can seriously study that long and digest/understand then yes I would say easily realistic without a doubt. 9-12 months minimum is realistic if you study every day regularly 3 hours and nail the exams first go. Its all down to how well you can hold the info in your head,believe me each chapter contains lots of bits to remember,it is vast,not difficult,just a lot to hold on to
personally i find anything over 3 hours and I start to just read the words instead of digesting the information,I am fortunate that in my job I can swop shifts for nights and get stuck in while getting paid !