Hello!

I finished my first custom recolor of the maid hair, and I want the package file to only include the adult and elder versions since they're the only ages with the lace hat. How do I remove the toddler-young adult versions? I tried the Quick Easy Hair Binner, but that only works with the natural color bins and not the custom bin.

Thanks!

You can either delete the PropertySet files, or zero out the "age" and "gender" lines for the younger ages (age 1, 2, 4).

YA uses age 40.

You'll want to keep age 8 and 10 for adult and elder. If you want you can keep YA since it can use the adult mesh and textures, so that's usually just a small fix in the PropertySet and/or 3DIR if they're not already set up as such (occasionally in the textures too, but more often than not it can be fixed in SimPE).

Is that in SimPE? I'm a total noob at this, sorry.

Yes. Unfortunately there aren't any ways to do it in Bodyshop, and I think Cat's binner is the only other way.
There's the Wardrobe Wrangler, but I don't think it allows you to remove ages (could be wrong, though).

.SimPE is absolutely worth learning for editing CAS files, and these kinds of edits aren't too difficult to learn

I love SimPE. I've already done some Sim modding (gender and genetic changes, and personality/interests/etc.) So I'm definitely down to learn more!

Well then, at least you have a starting point
A little bit more in-depth below:

You open the file you wan to modify (either "file --> open" or drag-and-drop it into the window) and make sure you have the "Plugin View" window active.

Then you find the "PropertySet (GZPS)" resources (there's usually as many as there are ages/genders in the file, you should check all of them).

Find the ones for age 1, 2 and 4 (toddler, child and teen, respectively - add in 40 for YA if you don't want to fix it). Either right-click the PropertySet and delete the resource, or write "0" for the "age" and "gender" lines (SimPE fixes the full numbers for you). The second method makes it possible to use the original files more easily if you ever want to add meshes for the younger ages.

Click "Commit" after each change in the PropertySet before you click other resources, or your changes won't be saved. You don't have to click "commit" if you right-click/delete.
Save when you're done.

The YA hair can be fixed (YA can use adult resources without any problems), but it depends on how the setup of the hair is. I'd have to see the files to figure out whether it's easy to fix or not.