If wearing TH gear does increase the chances of TH procing, it is not anything you would ever notice without parsing thousands of fights (IE something small like the 1% of the effects on them).
For the gear slots you are wasting to fulltime them, you would be giving up a lot more than 1% of your swings.
Sneak Attack and Trick Attack already have a significant enough increased chance to proc it without gimping oneself, in my oppinion. Speaking of which, some people SWEAR that Raider`s Armlets increase that chance even more. I haven't seen any testing to support this though.