Hey Zachatree, My best suggestion would be to read up through this link!
http://www.bountyfishing.com/howto/compete
But to answer your questions directly
#1 if you sign up for whole week, you get 7 days of fishing at a discounted rate, plus the benefit of being able to use the weekly code and being able to upload at anytime during that week. All tournies are ran on a week long basis. Sure if you only want to fish a couple days you could sign up for just them but 7 days is much cheaper. GL and hope I could help.
Mike :)
Better to be loose then tight!