I'm back-salting an acacia freebase solution. The pic shows what I am seeing after adding Naptha to the back salted then basified soup.

Am I right that I am to decant the naptha without those floating clouds of fats/oils? Is that what I am trying to avoid in this process?

A small amount of fat usually don't pose a problem for me, sometimes I chill the napthta including the fats, they will precipitate on bottom of the naptha - then I decant the naphtha and proceed to freeze precipitation.

The fat on bottom can be extracted with more napththa.

Sometimes it is possible to trap fats by adding a drying agent (e.g. Drierite) to the extracted naphta - it will remove traces of water and keep the fatty sludge on bottom so it will be easier to decant the naphtha. It might sacrifice some spice though...