Ok assuming I have an Improved Signature Weapon that is a 2 handed staff and ancient and elven to boot. It does Brawn +5 and Crits on a single advantage...

Do I have that right?

Unfortunately not, no. Each weapon can only be of one craftsmanship, so ancient and elven are mutually exclusive.

If you go with ancient, it becomes ancient an looses the elven craftsmanship. Sorry.

Ahhh ty. So the staff should be Brawn +6 damage and 2 advantage critical...

Is that right?