Jim That's a really good question. Let me try my view of this.
Back in the day the old school of thought was that the first pollination was always the fastest or best grower. I believe There was a study or two that set out to prove this. However the conventional view has problems with today's line on thinking.
Today we need to focus on what ever we choose to be the primary Fruit Sink. It is important that the Emerging FS be swaddled and treated as we would any young seedling. From the moment it starts to develop its critical to reduce stressors.
IMHO it makes no difference if the FS is the first or second on the vine. It's much more important that the FS has no competition at all. Treat it with the methods we have described and it will surely grow.