What information does the map provide? Each town has a selection of goods listed, some large-size, some small-size. What's the significance?

Thanks.

Port Royale 1 or 2? Sounds like 2 since the icons in PR1 all look to be the same size. If PR2 then I'll guess it has something to do with the supply state for the those items, be it 'efficient' or 'normal'.

It's only present in Port Royale; I recall in PR2 something can either be produced in a town or not.
And to answer the OP's question: they indeed indicate whether a town produces something with full efficiency or not. A large icon means 100% production rate, a small icon 75%.

Hmm, I wonder why I only see the icons as one size, but listed under Efficient and Normal headings? Maybe we're talking about two different maps - in-town versus sailing map or something like that.

Ah, you mean in-game. In that case, there is indeed only one size, but products are divided in two groups.
The OP must have been referring to the PDF map that comes with the game (and I got it they meant that map), where the different production values are represented by different icon sizes.

D'oh! You're right. Are you saying I should RTFM? : D

I always forget about the add-ons, except maybe key maps.

FWIW, Vera Cruz is a great home base once you get your revenue flow going. It has all the elements needed to produce several different items so you don't need to shuffle goods back and forth to make products - it can all be handled right there in that one town. The downside is that its separation from other towns can make it a bit tougher in the early game.