hi Devon
Em ct1 should be fine without ct3 there isnt much of a crossover . If you are reasonably good at math then ct1 should be fine as a first exam there is alot of sums of series , interpolation , and formulas by the dozen .
ct2 on the other hand has no math , its financial reporting ( cash flow , balance sheets basically everything I dont want to do in an exam ) and finance so description of all the types of assets ( shares , stocks etc ) .
if I was you I would open both sets of notes , read completely ct2 and work slowly through ct1 . My study method is to start exam papers as quickly as possible and I also like to know a bit at least about every part of the courses as early as possible . I actually studied ct2 first then moved onto ct3 then ct1 , but for my first exams I will be taking ct1 and ct3 together ( also ct6) , but I dont think it really would of mattered what order I had of studied them . That could be due to having a degree in math . math wise ct1 is much easier than ct3 anyways , well thats my 2 cents but I havent passed an exam yet so my advice could be worthless.