The main thing is you gotta do what works.

On my commute there is an intersection that follows a steep downhill. The speed limit is 45. I typically go 35-40 on the downhill (for San Diegans, I'm talking about the descent on eastbound LJ Village Drive between Gilman Drive and Via La Jolla Drive).

At the bottom of the hill the intersection has 4 lanes (left-only, straight, straight, straight-or-right). Since I'm going straight, the "by the book" VC thing to do is take the left side of the straight-or-right lane. Here's the problem: This is a narrow lane (10 feet, maybe), and, until recently, was right-turn-only. So motorists turning right from northbound Via La Jolla to go east on LJ Village Drive still expect anyone in that right lane to be turning right. That expectation, coupled with my relatively limited visibility as a cyclist, even when I'm riding on the left side of the lane, contributes to the right-turners "not seeing me". In fact, that's what happened this morning... I had to merge left mid-intersection to avoid hitting the motorist who turned right, right in front of me.

So, in this case, the VC left side of the right-or-straight lane is arguably not far enough left. I think from now on I'm going to have to take the adjacent lane to the left, and deal with merging back to the rightmost lane after I cross the intersection.

In the end, the VC guidelines like "choose the rightmost lane that serves your destination" are just that, guidelines, that are the best thing to do in most, but not all, situations. The main thing is you gotta do what works.

Another rule-of-thumb that can help to decide where to ride in a given situation is considering: where would someone riding a motor scooter best be positioned in this situation?