The difference between pot, reflux, and fractionating stills is the column. Pot stills having a shorter open column, fractionating stills with a long column with lots of packing, and a reflux being somewhere in between.
Pot stills are better for whiskeys, rums, and such while a reflux or fractionating still is better for vodkas and gins.
Here is the column I have.
If I was going to use this column to make vodka, I could get an additional piece of pipe to add between the top of my boiler and the column, say 18 - 36". I could fill this pipe with copper packing or rings and then I would have some version of a reflux/fractionating still and this would produce a better vodka without having to do multiple runs.