I would choose the third strand if you count from the inside of the "pearl-circle" because the copper in them appeal to me. I?d like the blueish strand next to it a lot too but if you look at the other side of the strand, furthest away, it looks like they turn less blue.
As for colour matching, I don?t mind different overtones, as long as they are all just as nice. Like in a tahitian strand for example, you tend to see pearls in all strands that are grayish and that don?t appeal to me a great deal so it put me off a bit. I?d prefer a strand with overtones and colours that are all just as nice, or else the ones I don?t like would feel out of place. They don?t have to match at all, I just want them all to appeal to me a lot. I think this is very subjective, though. I know there is people that love silver tahitians.
I don?t really care about size matching at all, as long as the pearls are graduating and the difference isn?t too big, like a 5 mm pearls next to a 10 mm. However, this wont ever happen. I want the sides of the necklace to look the same when wearing it though, if you have the biggest pearl/s in the middle. Maybe this was what Jerin meant.
The thing I think is most important when matching is to match the luster and blemishes. I like it when all pearls are just as shiny and when they have about the same amount of blemishes.