Personally, I would setup a test FOG environment just get FOG working.
I was in the same boat quite a number of weeks ago.
Setting up FOG on your established network will be tough to get right.
Use the standalone approach firstly.
It probably took me 40 to 50 hours of work to get a solution.
Last week using my Fog server , I was able to image 50 PCs in Win7 Sysprepped mode ready to join the domain.
My breakthru was seeing FOG actually working when I used a VMbox setup on my own PC following a YouTube tutorial.
good luck