I've completely rewrote this question as I didn't describe it very well in my first attempt, but it is still the same question. Let's say you have a bunch of files of varying size and need to put them on discs to back them up. These files do not need any directories preserved and do not need to be stored in any particular order. The end goal is just to leave the smallest amount of free space per disc. I do not want to use a compression program like 7zip to split an archive across the discs because if one disc is lost/damaged then all the data is unreadable. This is a question simply to learn HOW you would do this, I am aware storage is cheap and that this process could be time consuming. I'm just curious and want to learn how this would be done. As a very basic example look below;
I want to store these six files totaling 89MiB on two 50MiB discs. This is a very basic example. Increasing the number of files and having more random sizes is what seems to make this impossible, from a mental equation standpoint at least.
A.7z - 10MiB
B.7z - 20MiB
C.7z - 30MiB
D.7z - 10MiB
E.7z - 07MiB
F.7z - 12MiB
If I went by ABC order these files would need a third disc. However if file B and C go together on the first and A, D, E, and F go on the second it only takes two discs.