Double rainbow all the way across the socks
The title refers to the double rainbow-colored yarn but also to the classic YouTube-video Yosemitebear Mountain Double Rainbow 1-8-10.
If you intend to use the Zauberball rainbow yarn, I suggest that you spend some energy on pairing the two skeins of yarn as perfectly as you can, and then make two skeins that start at the same shade - or, you could make them mirrored.
If you use a different sock yarn, I still suggest that you pair the skeins to two 100 g skeins. It's much easier to handle that way!
Two 100 g skeins is more than you need, so you can make the leg section as long as you want it, and still have a lot of spare yarn.