If you make a good recipe nothing will settle anywhere.
It should suspend, if not use a combo of PGA, VG, and PG, rather than just one exclusively. I have had to do this more and more. (I typically use about 1/3 to 1/2 of oil drops used in PGA... i.e. 2 drops clove oil, 1 drop of PGA, 10-20%VG, the rest PG, and PG based
eliquid as the base, as of late.)
Leave a bit of air at the top (if not storing) because this helps mix when you shake the hell out of a bottle. I typically shake, flip, turn, shake, repeat. If it goes really cloudy and stays that way, try a few drops of PGA, or more PG.
(I can't really use VG based, as I get about NO
Throat Hit, and tend to use VG constantly with no breaks. So I avoid VG >20%.)