I wouldn't worry about sitting the exams over 6 sittings. Once you get into the rhythm of studying it's not as daunting as it first seems.
Depending on which school you choose, you can do 2 or 3 modules. I personally chose 3 to spread the load, but now looking back I'm sure I could have coped with two modules just as well.
Remember, many of the subjects are interlinked, and there are some basic principles, that if you understand them, will go a long way
regards
D-G