You can get away with putting a font of 10pt type in with a font of 24pt, but don't skimp on cases and try mixing type sizes that are close to each other. Spacing Material Spacing material is available from the same sources you get your type and is called spaces and quads. You'll need spacing material for each size of type you have, but not for each type face. The spacing is used between words in a line, at the beginning of lines to indent the first word, and to fill out the lines of type so that they're all the precise same length for locking into your press. To round out your spacing needs, you'll also need to find brasses and coppers.
Brasses are very thin pieces of brass and coppers are half that thickness.
These spaces are very thin, indeed, and need to be treated carefully to avoid bending them when inserting into lines of type. In a pinch, pieces of tagboard can be carefully cut as a substitute for these thin spaces, though that isn't a good long term solution. While type can be set directly into your press, it's a lot handier to set your type into a composing stick. A good composing stick is nothing more than a precisely machined adjustable box that can be set to allow the setting of differing line lengths. Good composing sticks are a treat to use.