Follow up ~
Liquifier was great. My favorite chorus sound on Helix by far. Very versatile too.
Still not a huge fan of Plastichorus, especially not in stereo, but I can see how it would work well for some people! For me it’s the same as my relationship with like MXR Flangers: can sound cool, but I only like a very narrow band of settings for my own playing.
Poly Detune is only mono (unless I’m missing something?), but sounds good for what it is :)
And Retro Reel doesn’t quite do what I want, but I like it a lot for other stuff. Sounds great!
So yeah, Liquifier (with headroom all the way up) does exactly what I was wanting. Thank you for the recommendations!