I hesitate to state an opinion here because I'm not speaking from a position of success and/or experience. I could be completely 100% dead wrong here. Read at your own peril...
One of the difficulties in selling singles is the public's perception of value. With so many individual songs selling for $.99, your retail price is limited. The sheer volume of material on the market is another factor. It can be difficult to find your audience (or for them to find your music). I know that sounds depressing, but it's the way things are at the moment. In many ways, established artists are struggling right now to market their material. The days when the label would bankroll your career and let you go off and focus exclusively on the music have passed into myth.
In my extremely uninformed and extraordinarily insignificant opinion, it's important to reset expectations. It might be a good idea to track down some stats on indie artist download sales to help you set realistic sales goals. I'm not talking about the one or two people who make it big and skew the numbers. I'm talking about the typical musicians. As I see it, there are two ways you can proceed. Either spend your time making music and spend very little time/money marketing until you've built up a wealth of material or spend an inordinate amount of time/money marketing each and every song. If it were me (and it's not), I would choose to spend my time creating content and worry about selling later. Whether you market the songs as individual downloads or as an album, you still need the material first. I suggest focusing on that without worrying about how you'll market it or how it sounds compared to your other songs.
It seems to me that the album format is a product of the distribution medium (record album/CD) rather than something of inherent value. If the medium has changed to single downloads, the album is of less importance. As a consumer, I still prefer to buy an album instead of singles because of the perceived value. My family, on the other hand, frequently buy single songs because they're not interested in buying the rest of the artist's portfolio. Go figure.
How's that for not really answering your question?