What exactly is the difference here?
This seemed like a good method, and I thought i’d try this. Is A OBE the same thing as a lucid dream assuming I know i’m dreaming? Or is there something vital i’m missing or misunderstanding here?
Thanks!
First let me say that I only briefly read the link you provided. However, From what I saw I think it would be a good WLD/MILD technique. I just think it makes things more complicated than they need to be but, that is just me. Good luck with it and please feel free to share your results.
Now what is the difference between WILD and an OBE? Well that depends on who you ask.
Many believe that an OBE is really a WILD and therefore is just a dream. Everything that happens is in your mind (dream) so your environment is unstable and you can change it at will. Since it is a dream you can interact with things, pick things up, etc. Also since it is a dream you can do things like fly, pass through doors and walls and even utilize near god like powers.
Many others believe that an OBE is a method where you project yourself out of your real body into this world. So everything you see should be as they would be as if you were in your waking state. Also, in an OBE since you are in this world (not in your mind) therefore things are not changeable. You can do things like fly and float through doors, walls etc but, you can not change things or interact with objects (move /pick things up, open doors etc.
Which belief is true only you can decide for your self. So far neither side has “proven” their beliefs.
Some people say there can be intermediate things, dream-like OBE or OBE-based dreams… They say that even during a classical OBE your mind can continue working in dream mode and create illusions of things. The picture you see is kind of a superposition of a dream over real-life things. If it is true, it can be impossible to set a border between an OBE and a dream about a familiar place. But a LD does not necessarily happen in a familiar place, so the farther things are from reality, the more likely it is that it is just a dream.
In fact, I don’t believe in astral projections as a common phenomenon. 
But if they happen, it would be rather logical, if such mixtures of astral vision and dream vision happened even more often. So even during a “correct” OBE, things can look not what they are really like. Or things can look in their “astral versions”, too, and you will be able to interact with there projections… 
So it is impossible to prove that OBE is just a dream…