nice progression going on.
To eliminate the long tail get and use a wave editor. After you export the song open it in the editor and trim it.
This is the one I use:
http://www.nch.com.au/wavepad/index.html It is free.... after the trial period it offers the option to activate the demo version with limited function. Normalizing, converting to MP3, and trimming are part of the features that remain functional.
The song is cool and laid back, but some of the scales and riffs are not in the proper scale..... notes are not fitting in places.
You can fix that with a few options depending....
1. be sure the key matches the chords you are using.
2. render several tracks, not just one, for that given instrument and use creative editing.
3. use melodyne to fix those notes
my 2 cents