Secondly, what route is better ...taking the double exam or the single? I have been contemplating which exam set to take.
I'd say it depends on your comprehension/memory ability. If you are able to study say 10 chapters without forgetting the 1st and 2nd chapter once you reach the last. If you are able to answer at least 80% of say 800 questions, The single exam might be for you. The double otherwise. I personally took the double, since I was going through CCNA academy material which is in my opinion very deep and dens and I have poor memory.