Sharing a palette among sprites in different files

[chickendude]

I've got a palette for my main character, but now i'd like to add some other sprites, things like enemies, NPCs, etc. However i'm not sure how to use the shared palette option in grit. I've seen the -pS option but i'm not quite sure how to use it. I've currently got a grit file for every set of sprites (my tiles, main character, and the font), but i've read i might have to set up a directory-wide grit file to use the shared option? I'm using the standard make file from devkitPro. I wouldn't mind putting all sprites in one .png file, but in that case they'd all have to be the same size, wouldn't they? That's currently not the case. I have some sprites that are 16x32 (well actually 16x24) and others that are 32x32 and can't figure out how to get them to share the same palette so that they can be displayed at the same time using the correct colors.

I saw headkaze's thread which sounds similar to what i want to do, but i'm not sure how i'd implement something like that in my makefile (here, not sure if the URL will show up or not).