heres how to fix your problem 5/5 SA merits and 5/5 TA merits
i have 24% haste at most i hold tp for 1 extra round of hits (2hits) and i have no group 1 merits on thf. and im using less delay then you with 201 (x's knife) and 150 (sirocco) and not to mention you have SA and TA i mean it happens sometimes that both are down but not often enough to drag my DoT down to badly. do 5/5 SA 5/5 Triple attack and you should be fine.
and its more about your gear compared to another thf's just because thats your parse if i was to parse and use the Pharpe and blau then Blau sirocco id get different results but blau/sirocco will still win... why are you fighting this still?
you NEED more dmg on your main hand weapon to have the upper hand w/ high delay and a little more dmg (like 30-50 dmg if that) compared to -2 dmg and low enough delay to have a bigger impact then +2 dmg on the dagger.
you seem to be looking at WS dmg more then anything and thats not the factor thats gonna change what you want to prove. you do a little more ws dmg and maybe 1 more dmg per hit but im attacking faster and doing close to the same in ws dmg,
i attack faster i do close to the same dmg and i can ws more then you why doesnt that win!!!?