Good solution? As he pointed out, the camconst.json alone won’t solve the problem for the DNGs. The EXIF data must still be manually edited for each file. It’s better described as a workaround.
It’s also no perfect solution even for the CR2 files from the G9, as I shoot both IR and visible light pics to achieve special effects, necessitating repeated editing of that file.
Where should I look for those 2 lines you mentioned? I plan to create a personal version anyway in the middle future (after dusting my programming skills a little 
), with some special filters for scientific use.
Also, could someone tell me how to calculate the matrices, as ilias_giarimis did on a suboptimal shot before I posted the pic of the CC?