Ok, as far as the mounting for the fork bag, it really is fairly self-explanatory once you get it (even I can do it). It mounts just under the headlight and the straps wrap all the way around the little piece just under that (where it says Royal Enfield). I don't have a way to get pictures right now, but trust me you'll get it once you see it.
As far as aftermarket solutions, I prefer to go with our host for several reasons over E-bay. 1: I know what I'm getting, 2: I know they fit (I'm not in a position to modify anything myself.) 3: I want to support the network that continues to bring us our nifty bikes. So, while I know that I could source something cheaper I think I'll stick with either an Nfield system or possibly D&D system. I like em both!