It depends how the line is set - typically they are slightly angled so the committee boat is favored. This helps the committee boat see who is over early since they're likely to be closer to them. If the start line is angled this way, you will be starting a boat length or more behind the other boats by going to the other end. This might be worth it if you can get clear air and make up the difference with speed. Sometimes you can catch competitors snoozing if the line is angled so the pin is favored. Either way, to cross everyone on port means you have had to outrun them before you tack back which is not easy.

We first decide which end of the line is favored, then we decide which side of the course we want to be on. If we know it's going to be a log-jam at the committee boat and we want the left side, a middle of the line start or even further down is sometimes fine. If we want the right side of the course, sometimes we'll put up with the log jam and accept the possibility of being behind a couple of boats at the start just so we have a clear lane to tack onto port to go right. It's a matter of deciding what your first upwind strategy is going to be and how much starting-position risk you are willing to accept to try and get where you want to be.