Cool beans.
Not that I'm a recording guru... but if you're working with a 32bit mix engine, which you probably are if using Logic... one popular approach, is to create your mix where it generally peaks around -12 to -6dB. That way, there's plenty of headroom for processing the 2mix (commonly referred to as 'mastering'...but it aint really 'mastering')
Take the mixdown, and run it through a comp-limiter-maximizer to squeeze it to a more commercial volume. Waves 'L' series ultramaximizer, or the like, or, one of a myriad of the tube-style compressor plug-ins will work great. Dial up a 'mastering' preset, and tweak the threshold, and attack-release times to taste. Good time for final EQ here too.
Sorry if you knew all this already... and, there are a zillion different ways to get results besides these.
Still, your stuff sounds great.