Warrior notable skill 2hand as 1hand explanation

Hi!

I have a question about the skill tree node for warrior that allows you to use a two 2-hand weapons as a 1-hand wepon.

Once that I activated this node, the two 2-hand weapons are going to scale the 1-hand weapon bonuses or 2-hand weapons bonuses?

That's quite important because I base it all the skill tree for one hand weapon bonus nodes.

Also, those 2-hand weapons can be dual welding or the second slot can be just for the shield?

In base at the answer I'll invest in different nodes so I'm waiting for you guys ^^

Thank you very much!