Ranger: dual wield 1HS or use 2HS?

[Bardolap]

Apologies if this has been asked before, but searching the forums for short, commonly-used words doesn't get the results that I'm looking for.

I have a level 45 ranger and am wondering what the DPS comparison is between using a 2HS vs dual wielding 1HS weapons.

Currently using Lamentation (9/19) primary and Sarnak Skullsplitter (12/26) secondary. How doest that compare to either Nature's Wrath (29/44) or Silver Swiftblade (16/24)?

What kind of dmg/del should I look for in a 2H weapon to be equivalent? How does double atttack affect primary/secondary weapon attacks?