I think the homemade ones are actually better looking than most shop ones.
The shop ones are typically too big and the colour usually looks wrong.
The homemade ones are usually uncoloured latex, which gives them a reasonable pakeha skin colour and also makes them slightly translucent which makes them more natural-looking.
To make them you just make a clay (or fimo or whatever) model of the eartip, paint it with liquid latex, then peel the latex off once dried. You can mix a little bit of paint with the liquid latex if you want a different colour.
It’s much simpler than making a latex mask, because you’re not making a plaster negative.