I know this sounds goofy, but......
I'm making some prints, and one of the negs has a Macbeth color checker in it. The light grays on the color checker are slightly Cyan on the print. To correct, I need to subtract 5 or 10 units of Magenta, but.....
I CAN'T!!! My filter pack is 0 Magenta and 50 Yellow!!

Fuji Crystal Archive Type C glossy paper
Tetenal RA-4 room temperature chemistry.

Now what???