Hi Jeffrey,
Well maybe it's because I'm staring out at a white winter wonderland right now, but this piece actually makes me feel like I'm on a patio at a beach-side watering hole enjoying the breeze there
I don't know how this might differ from your "live instrument" version, but I love the vibe (and the vibes!). If this was done via mouse note entry, you've done a fabulous job of capturing a live feel. I listened with headphones on, and really enjoyed the stereo movement and spacing that you have - well done! There are a couple of very short solo passages that feel a little "stiffer", but overall this is good stuff.
Re. the sounds and volume(s) differences, you may have originally composed this when the GS Wavetable was the default sound device. We have since implemented our own NS Synth, which uses soundfonts (with Composer you can choose which one) and so the instruments will sound a bit different. You can use the GS Wavetable if you want, but given it's latency issues and the better sound quality of the instruments with most soundfonts, we typically recommend using the NS Synth and finding a soundfont that you like and re-adjusting volumes if desired.
Keep 'em coming!
Sherry