Can you make an option in the config to overwrite the string shown in the matrix that says it is craftable?

The german word "Fertigungsmatrix" is quite long, and I would replace that by a simple "F" or "FM" in the config. Otherwise the word is so long that it overlapps the other items.

On which version are you?

I fixed this a long time ago on 1.12:

https://github.com/raoulvdberge/refinedstorage/blob/mc1.12/src/main/resources/assets/refinedstorage/lang/de_de.lang#L6

It just says "Craft" in German on 1.12.

1.10.2 is unmaintained.