I can tell the future, so let me help you out:
You're going to finish this bike with a half link chain and a magic ratio but have a chain that's just a little to tight and binds up on every chain rotation making a popping noise. That or you're going to have it be a little to slack and get annoyed by it.
After buying your eccentric hub to fix the problem you'll finally feel like the bike is finished.
Then you're going to get on bike forums and read thread after thread of sweet track bikes and begin to covet the magnificent track ends. You'll look at your bike and wish you'd started with a track frame so you could put whatever gear, chain, and hubs you want on it. Looking at your bank account you'll wonder why you didn't save all the time and money from your eccentric hub endeavor and just buy a track frame.
In the end, you will buy a track frame and wonder why you didn't do so in the first place.