In the end, it is best to let your taste buds decide how much dried oregano you should use in your recipe. Also keep in mind that a packet of dried oregano that has been lying on your shelf for several months provides less flavor than a packet of oregano that you have purchased recently.
You can certainly choose a CMYK or HSL dialog in the fill and stroke and all colour pickers, but it converts all colors to 8 digit hex as you willl see in the bottom of the picker. Since RGB and CMYK spaces are both device-dependent spaces, there is no simple or general conversion formula that converts between them.
CMYK creates different colors in a subtractive process using four colors or inks: cyan (blue), magenta (red), yellow, and black. Chances are your inkjet, bubblejet, or laser printer at home has a CMYK or CMYK variant setup. There are many RGB colors that CMYK printers cannot reproduce.