Sorry for the delayed response, but I have been out riding and camping for the last 4 days. Besides not being able to start the bike one day and having to jump start it (which I won't clog this thread up with the details of, and just asked for help on in a different more appropriate thread...), everything else worked great including the new sub frame tank, which really helped ease my mind on one long day of riding with no gas around! My buddies were on reserve and fumes by the time we made it back to camp...
To answer your question about the routing of the vent line, I ran it directly from where you break off the tab of the subframe mounting bracket down the right side of the bike under the seat (yes, I did remove the rib on that side almost completely just to make sure it didn't get pinched) and down the seat hold down catch and zip tied it to the stock fuel line as they show in the instructions. From there, I routed it up and under the left side of the main tank to avoid getting it too close to the hot pipe on the right side.
Here is the number one tip you should pay attention to that I'm embarrassed how long it took me to figure out as the logic is so basic... When you mount the T fitting that connects your sub frame vent tube with the stock vent tube, make sure that you put the T fitting/adaptor as high as possible, because if this is lower than the gas level in your main tank, it will leak due to plain and simple gravity... This is what was causing my leak, which was then coming out of the vent tube any time I filled up or leaned the bike causing gas in the main tank to be higher than the T fitting... To fix this, I actually ended up mouting mine on top of the tank and then used a Husaberg fuel tank cap vent on top of that. I'm going to try and attach a picture of this, but this will be my first picture, so no guarantees on if I can get this to work... Good luck and have a great ride!