My work flow is very similar to Guitar Hackers. After getting each song mixed I render it to a WAV. I then import each one as a separate track but I stagger the WAV files and leave them all enabled. I too use ozone and use an instance of ozone on each track. I start with the same preset and adjust from there. I use a preset designed to add saturation and enhancements. I tend to leave the mix bus empty until all tracks are treated with ozone and balanced for volume.

Staggering the WAV files (songs) allows me to very quickly jump back and forth listening to each file while playing, altering the preset and volume to bring them in to balance with each other. Once I'm happy with the overall sound of all the tracks I put ozone on the mix bus and use a preset that adds a volume boost and limiter (remember the setting). This is only so I can gauge where the final volume will be. Once I'm satisfied I will render each track as a WAV with its own Ozone setting. Then each track can be reloaded individually and the volume boost and limiter applied per the setting you had earlier. Then render the track as a final.

One thing I will say. If you can't get a song WAV to fit well with the other songs go back into your song and remix it.(this is much easier than trying to get the mastering plugins to do it) Then render it again and add to your CD track adjusting as before and recheck it. You may never reach the level of a true mastering engineer (or you might) but you can get them sounding pretty damn good in the mean time.

This is my way of doing it and I like the results. This may not be the way most would do it. I'm not an engineer and probably will never have any of my songs or mixes go commercial but I'm happy as a hobbyist can be.