Move Rekordbox files to ext HD?

This maybe a stupid simple question, but only just did my first USB gig at weekend and loved it.

I have all my DJ tracks and files on a large ext 1TB HD but with Rekordbox installed on my Mac, I dragged the 60 or so current tunes i have into Rekordbox and think these have gone into my Mac (i also renamed some for the USB stick) did this copy and make a '2nd version' of the track?

Could I move my Rekordbox folder of tracks back to my ext HD so everything for DJing is together (incase I reformat etc?) is there a simple way to move my base folder of Rekordbox to an ext HD and it always launch (and add new tracks when i get them) to the ex HD?

Secondly I did the format, BPM, key and cue points, plus all my settings - which all worked great in the CDJ2000nxs on the night, the only thing was my settings didnt really update? I chose +10% on the settings but CDJ stayed at 6%?? What did i do wrong?

Thirdly! Can I use Rekordbox to organise my whole huge DJ selection (on the ext HD) so they are BPM and key sorted into Rekodbox playlists BUT never export them all for a gig to my USB stick? I probably have about 80GB of tunes, which I think would benefit for them all inside Rekordbox as a key/bpm system BUT a 16GB USB - do i just only TICK the playlists I want sorting to export and not my 1000's of tracks, loops and samples?

Thanks for any help as I've just converted to USB and love it.