yes, you can match the individual channels and produce individual rgb curves. if people are interested, I can post a modified version of the script. in my (limited) tests however this is less robust – it works well for the original image but not so much if you try applying the same curves to other images…
that’s something I haven’t tested – I didn’t even think about it to be honest 
I would be surprised if the impact turned out to be big, but it definitely needs to be checked