That should all work very well. Nice and tidy. Won’t be good for your eurorack sockets having heavy adapters hanging out of them for long periods of time.
I’m going a slightly different route.

I bought 2 of these:
http://www.dv247.com/cables/cordial-dual-mono-jack-to-stereo-jack-cable-1-5m–200458
And four of these:
http://www.thomann.de/ie/thomann_1011_miniklinkenstecker.htm

I plan on soldering the mini jacks on to the ends of the insert cable.

I purposely picked the cordial insert cable as the shields screw off giving easy access to the jack soldering bits. Don’t have much soldering experience but hoping this will boost my DIY skills and give me nice tidy no adapters no fuss solution