yeah, 30% proc and 30 secs duration, and both increase linearly with tp. At 300tp we get 50% proc and 1.5min duration (and Rudras gets a huge ftp bonus to boot lol). I'm not totally sure on these aftermath increases but it's what friends told me. It might even be worthwhile to use a 300tp rudras every so often, idk. Anyway, if mandau is indeed 5% proc then it's like i posted, we have 30% damage boost (at 100-199tp) vs 10% damage boost.
In the end the old maxim still hold its name, shit is situational and more so for thief with sa/ta being a huge variable. There can be situations where sa/ta can be used freely just as much as situations that we have to forget them.
Raen meant that to full time the aftermath. It lasts 30 secs and we get 100tp in less than 20 secs. Since lv1 aftermath overwrites itself, we can ride it by spamming the ws. And that's what jobs with "good" ws have as an edge over us, they can just spam their ws and hack away, while we have to think of sa/ta timing an position. But if the aftermath didn't overwrite itself no one could ever have it up 100% of the time unless we timed its duration with our tp gain speed.