I have a 200R4 with a 3600 rpm stall 3-carbon fiber disc lock-up converter. It is heavier than a non lock-up converter, but it is also like having a 5th gear. It drops the cruise rpm about 350rpm when engaged. Unless you are building a strip only car, it's worth looking into.
I wired mine with a 12V toggle switch that passes through a normally open pressure switch screwed into the 4th gear pressure circuit in the transmission. That way, it only will lock-up in 4th.