I prepared a rotation that is using a WNII finisher. But I am not convinced it is even possible to use it. Here it is :
And here is my personal rotation from my guide :
Yes, the WNII finisher leads to a 12 HT's rotation instead of 11. That's clearly an advantage. I made a WNII rotation that needs the exact same amount of TOTT, 5. It does require 6 additional base CP, 394 (can be reached, but with good melding). The big drawback is : you need 5 TOTT proc under 13 steps. That's not going to happen. My usual rotation needs 5 TOTT proc under 20+ steps, which is quite common.
And in fact, if you get 5 TOTT procs under 13 steps, there is a HIGH chance they will come under SHII. If so, you need an additional SHII, so in fact 7 TOTT proc under 13 steps. No, clearly, I wont bet on this...
(hope my Excel WNII rotation has no mistakes, did not test it IG)