Something I've been thinking about:

My character has the Mass weapon and shield, and Dagger proficiencies.
Suppose, during combat, I somehow lose my morningstar, and pull a knife instead, how will that affect my CP?

In other words:
With the Dagger and Mass waepon and shield proficiencies, what would CP be when fighting with a dagger and a shield?

Saxon warriors who could't afford a sword would have a large scramseaxe (war knife) to use with the sheild after the spear work was done with. So I would use the Sheild and Sword default you get from mass and Sheild.

Sounds like a tough one. Has there been any official ruling on using a seperate prof. in each hand?
If one is higher or lower than the other, that wouldn't be ideal because one shouldn't effect the other, in this case at least. Using a seperate CP for each wouldn't work either.
Maybe average your 2 CP's together? But if there's much of a difference that may raise or lower your skill too much as well.

This makes me think of anothe problem. If you have the sword/shield and mass weapon/shield prof.'s, and one is far better than the other, how come your shield skill will suffer with the lower one?
But on that note for consistency, with a dagger and a shield, you'd use your dagger prof. as "dagger and shield".

First, remember that you essentially fight using a "style-proficiency", not a "weapon-proficiency". Fighting with a dagger/shield combination will pretty much equal a shotsword/shield combination in the way it is used. Dagger alone looks and works much like wrestling (there really isn't much of a difference). So you wouldn't be able to put that to use very well.

And the problem with one shield proficiency being much better than the other isn't one at all. They default to each other with a difference of about 1. :)

I definitely disagree about the shield use. I would not change the way I use a shield regardless of my offhand weapon. I don't really see how you could.
And sure sword and mass weapon default to each other closely, but once you put points into it it's no longer a default, potentially leaving a good gap, along with only having the basic strikes from a default.
I am seeing how it would best resemble shield/shortsword now though. Sounds like the best way I guess.

Dagger and shield would be closer to a sword and shield combination than that of a dagger alone.

But it also seems, Caz that you believe that shield proficiency is something that will not suffer if you use a different weapon.

No one ever trains in shield only proficiency, like shield and bare hand. It is always a combination of 2 weapons. As it is a combination, when using a weapon different than your usual combination with a shield, yor overall proficiency will suffer, I.E. less cp.

Keen of you to notice no one ever used a shield alone, at least not normally or on purpose. But you use the shield exactly the same wether in your other hand there's a sword or a mace or what have you. You don't somehow stand with the shield in a different guard or block differently with different primary weapons. A shield is a dual weapon item, but it's used in it's own fashion. It only changes if you pick up a different shield design.
But I bow out to the rules as is, I don't see a better way of handling it, good as is as far as I'm concerned.

Well, I guess my point is that your tactics will change when you are using a dagger, arming sword or 1 hand flail. And when using a primary weapon you are unfamiliar with, both offense and defense will suffer. Moving to a strike attempt and then recovering on a missed strike will be different, due to reach and striking methods. Learning how to close on an opponent is a necassary skill with shield + dagger, not very important with spear + shield. The one who has trained with spear will be not comfortable closing, and may well open himself for an attack with an inept closing attempt.

These are somewhat extreme examples, but there will be some differences in your defense ability if armed wih an unfamiliar weapon and attempting to attack (perhaps if you only stay back and shield yourself your shield skill may be as good, but no one is going to do that).