That’s a lovely image, I’m a sucker for bi-colour images
Perhaps my only feedback is it looks clipped (check the histogram?) and hence the deep contrast.
Something else you might wish to try (if you haven’t already) is a Foraxx HOO palette using the following channel mixing:
R: Ha
G: ((Oiiixa)^-(Oiii*Ha))*Ha + -((Oiii*Ha)^-(Oiii*Ha))*Oiii
B: Oiii
This then puts the Oiii data into both the G and B channels as suggested by John (Oska) below. Alex