Hey BTM_Pix,
I know it has been awhile but can you share how far along you got with reverse engineering the http api for GH5 ?
I was about to start the same work, in my case, to get a remotely controlled time lapse with bracketing enabled.
Let me know if you think we have something in common on this!
Edit: For posterity, the handshake and subsequent connections worked for me, but looks like the cgi script is flaky (sometimes gives err_critical back).