I'm having a similar issue with the CLS and my full spectrum camera. While I can get the background and stars more or less neutral, the nebula colours are so strong in Ha that there is little O3 passing to give contrast so nebula become just red. Even though the CLS does pass O3, the balance between O3 and Ha seems off.
I'm experimenting with stacking colour filters to try and get a more balanced look to the pics, but most filters are too strong and swing the colour wildly one way or the other.
Another way might be to stack two sets of frames, one with a Ha bias and one with an O3 bias. Add a blue then I'd have RGB.

But there's goes the plan of OSC.