The blurriness is now really starting to get to me; I've given this a few days and I love the immersion, but as a whole it makes the gaming experience irritating.
Really sorry to hear this. I guess there is a chance that you are unfortunately at the extreme end for usability of the Rift ( why they haven't implemented a means to adjust the lens spacing I don't know) or perhaps you have a faulty Rift. On the off-chance that it can still be fixed there are a few points to consider, some have been asked but you never replied to them.
1. Did you confirm your IPD?
2. Did you follow the exact instructions for calculating your IPD? Key points are to extend the Rift so its fully extended (using the side screws for eye-relief) and set the correct setting in the configuration panel prior to using Oculus tool for calculating IPD.
3. Do you feel eye-strain when using the rift, as though your eyes are having to focus harder to bring the image into focus? If true then that suggests to me an IPD issue. That the IPD is wrong and thus the image from the two eyes doesn't quite line up/overlap exactly to give the correct 3D effect.
4. Blurriness can be an indication of incorrect eye-relief settings. I played around with the physical eye-relief settings one time and noticed the image became blurred when it diverged from the setting in the configurator.
5. Have you tested other Rift demos? The built in desk demo is good to start with, and there are plenty of other free demo's around to try. If other demo's suffer the same problem then you are back to incorrect set up, dud Rift, or sadly the Rift just not being able to work for your eyes. If other demo's don't suffer the same problem then obviously its something in E

doing this.