I am still mastering the new songs, but I think they're coming along. As part of my production process, I upload new versions as I go so that I can then listen to them on different devices. The other day, I had the entire album sounding great on my headphones and monitors, but then when I burnt a CD of it to play in my car, it was really bass heavy. That same mix, when I played it through the shitty little speaker on my tablet, all that was coming through clearly was the mids.
As someone who is self-taught in all of this stuff, this is more or less my understanding of the mastering process: keep fine-tuning the songs until they sound as good as possible (within the realistic limitations of DIY home recording) through whatever speakers I play them through. I read a long time ago that this was how Frank Zappa did it. His theory was that once an album sounded good through even the worst system, then he knew that it was done. While I've admittedly never really gotten into Zappa's music, I've always thought that this approach made a lot of sense.
In any case, if you want to follow along as I continue to master these songs, I'm uploading new versions usually at least once a day, sometimes more. You can witness firsthand the evolution of this album here, as I continue to take it as far as I can with the equipment I've got. Frankly, mastering seems like a misnomer, since this is one of those things that I don't know that you can never truly master, considering that the process and the products are themselves part of a constantly evolving enterprise. I will say, however, that the more I do this stuff (while, of course, learning as I go), the more pleased I tend to be with the ultimate result. I hope you like it, too.