I'm generally all right with punctuating dialogue, but this is something I've struggled with a few times.

How do you format dialogue in which a character performs an action while speaking, or pauses in the middle of a sentence to perform an action? I'm thinking of something like:

Bob laid the shirts out side by side. "This one," he said, pointing at the green shirt, "is too big. But that one--" he pointed at the blue shirt "--is too small."

For Bob's second sentence, about the blue shirt, is it appropriate to break up the dialogue in that way?

I usually use the construction used in the first part of Bob's speech. That is, I'll use a speech tag ("he said") and connect it to the action ("pointing at the shirt"), which usually seems to work. But when it comes to situations like the example sentence, I hesitate to do that twice. Writing

"This one," he said, pointing at the green shirt, "is too big. But that one," he said, pointing at the blue shirt, "is too small."

feels too repetitious and clunky.

How do you indicate that a character is performing an action in the middle of a sentence?

Not sure if this makes sense. Hopefully I've explained what I'm getting at.