With all due respect I'd say you are a rookie at this. Your questions are good and better asked now than after you buy arrows. It's all good stuff to learn, but shopping on the internet is the last place you should be buying till you get more experience. Visit your local pro shop and get hands on help for now.
I've been shooting compounds for almost 40 yards and forgotten more than most guys will ever learn and I still don't buy on line. The little money you save is not worth it and often you end up getting the wrong thing and end up buying twice anyway so the saving goes out the window.
Ask yourself this. Are you knowledgable enough to tear down your bow and put it back together and tune it up again? You may have a local shop that needs your business to stay in business. If he can't make a living he closes his doors and who is going to do all your repair or maintenance then?