You are right, I misspoke (mis-typed?) my fingers clearly out typed my brain.
To be clear. I would go with a tri-radial square top.
On great sailing weather
a square top generates more power than a pin head
main, for a number of reasons, but mostly because it has less drag, and a better air foil shape.
As for reefing. When a pin head is reefed, not only do you decrease the sail area, you also move the CE of the sail forward. This occurs because the foot length decreases relatively fast. This can cause a boat to develop significant lee helm
, particularly if the CE of the normal sail plan is relatively far back.
On the other hand when you reef a square top main the CE stays mostly the same, because the foot stays almost the same, you just reduce the hoist height. This keeps the CE in roughly the same place on the boat, regardless of the amount of sail that is projected.
A good way to see this visually is to take a piece of paper and fold it in half so you have a piece that is 4"x11" and fold another so you have a triangle with one side 11". Place them on top of each other. Now cover up the same amount of area from the bottom of them. What you will see is that the triangular shape looses a lot of area from the back first.
So in my estimation, a square top is a better performer in all situations. The only place where it is a problem is dealing with a backstay (which may be the deciding factor), since a square top main cant be tacked easily thru a normal backstay.
This is exacally the reason why all offshore racing classes
use square top sails
. It isn't really to maximize sail area (they are pretty much all limited in sail area anyway) but to back the boats perform better, and more controllably with what they have.