yes ive tested. 100% certain. The trial TP +100 weapons work in offhand.
I need to test if they stack with martial weapons but i havent had the time.
Doesnt open up as many options as one would think. Martial knife + fusetto+2 would make aoelian edge pretty nice at 100%. Even outside abyssea. And inside gales, hells guardian and ultima added to the martial + fusetto could make for some great mobbing.
possible offhand for a Dagan using whm soloist. With an HP + WS set and smiting blow atma could easily get a 2k hp heal dagan at 100%. probly around 700-800 mp return with an MP plus ws set.
and then farsha. Other than that there isnt much use for the offhand TP bonus trick.
ALSO, the 2200-2800 was with 1 slot going to Razed ruin so really wasnt much dps lost there. Mainly just hurt losing the OAT offhand and the regain from VV. The slower WS frequency. But doesnt mean with a little poking and prodding that u couldnt fit it in. I definately think the whole using stalwarts and Richardets and rampage then switching to Renauds ascetics and cloud with blinding horn VV RR could be the best of both worlds in an exp part situation.