You should have in mind the few choices that you wanna get already.
Probably you should go for a final audition again on those few, then make your decision. Use the same tracks that you are familiar with when doing audition on them. If you need to, probably write down the pros and cons of them somewhere. Then at the end of the day go and tabulate and see which one fits you better.
Imo, using the iphone5 as source might not be a good thing, some earphone shine more on better source. So you might not be hearing the potential of those earphone with a iphone5. Perhaps you should try using those dap that are available in the shop to do the demo. Bring a microsd card filled with your familiarized songs.