I think this is the standard fuel line routing.
You're pretty close: there are 2 types of single-outlet petcocks on the K5/6 and F0/1 bikes. On those where the petcock outlet exits the petcock horizontally toward the bike's center, the hose enters in between carbs 1 and 2, not thru that hole in the bracket. On the ones where the spigot points downward from a 17mm long squarish manifold on the back side of the petcock, the hose goes thru the hole in the bracket and meets the brass tee.
Another thing you might find: there is a third style of petcock from the F1 where the spigot points backward, toward the back of the bike, and this one cannot be easily used with the round-top carbs, as it is intended for the PD carbs. Some tanks have been swapped onto F0/1 and K4/5/6 bikes with these petcocks, causing lots of e-mail to come my way...
If your petcock does not have the little filter bowl on the bottom, then your carbs MUST have the little screens in the float valves. These appear in the type 086/a carbs and will not fit into the 657a/b or 7A type carbs, though, leaving you with having to install an inline fuel filter. When THAT happens, the easiest way to make it work is to run a long hose to the top of the airbox area, with an inline filter along the way, and tee it back there before going forward to the carbs. It slows fuel delivery during hard acceleration, but unless you're running 13-second quarter miles with it, you won't notice.
