Sorry I meant to reply sooner but I got busy.
Interesting information, thanks. So when I select rainbow wave, it defaults to some other effect that isn't listed, when I exit iCue. The effect works quite well, in that it isn't disjointed or slow on the QLs and faster on the SPs. It starts with the first QL fan art the front of the case (280mm rad), then the second QL also at the front, then the two exhaust SPs on a 240mm rad, and then the final SP (set to intake, filtered), and then back to the QLs at the front. It's a colour that goes through all these fans in that order, and cycles all the colours of the spectrum, in order. So it's a multicolour affair, per cycle. It isn't like the colour shift effect, from iCue's list.
The rattling is mostly gone, but I hear it randomly appear when I least expect it. I have some LLs on its way but honestly, the cooling in getting with this case and with this setup, I'm happy to tolerate the occasional rattle from the fans. It is most apparent at the very low RPMs.