Additional pickup advice for Godin ACS Slim.

Kandinsky

I've been playing my Godin ACS Slim unplugged for a few years when I was confined to my bed with an illness. During this time I've developed a technique that has a lot of emphasis on the percussive string pops and slaps along with hitting the guitar soundboard. A bit like a rockabilly double bass sound.
Now that I'm a lot more mobile I've been plugging the guitar in and while I like the medolic sound, the percussive part has been lost.
I'd like to add a second pickup to the guitar in order that I can amplify these two sounds (normal medolic and percussive sound) on separate signal paths and wondering how to achieve this.
I'm not sure whether an internal mic in the chambers of the guitar would do it or a sound board transducer would be better.
Could anyone offer some advice please?