Re: How to build a duel wield attack
If all he wants to do is attack with the two weapons, then the various methods outlined by others on the thread accomplish that well. Which one to choose depends on what you and he feel best matches the flavor of his two weapon style.
But if he wants to do different things, like attack with one and block with the other, or attack with one and hold the other to attack/block in a future segment, then I think limited SPD is the way to go. The simplest way is probably to have him buy additional, Limited, SPD equal to his base SPD. A limitation of "only to take additional attack/defense actions with a second weapon" is probably worth about -1. He can't move with this SPD, he can't use it do double attacks with a single weapon, etc.
So if his character is SPD 3, he buys +3 SPD with that Limitation for 15 points.
To keep things simple at the table, I'd say he only acts on the Speed Chart at his base SPD, but whenever he acts he gets both actions. I'd probably also say if he does not use both actions at the same time, he has to use the held action in a future segment. For instance, when his phase comes up in segment 12, he could attack with both weapons right then. But if he chooses to only attack with one weapon and hold the other, the second weapon can not act until segment 1 of the next turn.