TSS or LPC? *** Rogue help needed!

Hey guys, 3.6k Rogue here. Question for the other *** rogues: I have 1.8 The Dusk Blade in my MH and 1.6 Titansteel Shanker in my OH, but trying to test DPS between TSS and 1.4 Librarians Paper Cutter is difficult. I get similar numbers: TSS tends to up my raw DPS in a shorter amount of time, but logically-speaking the 1.4 LPC and its poison procs should be out DPSing the Titansteel.

My question essentially is: IS the .20 second difference that big of a deal to be using a 1.4 weapon? Or can I get away with the 1.6 Titansteel Shanker?

LPC is 1.3 and yes, it is that big of deal, you should be using 2xLPC then 2xWD from Naxx25.