Remember ShiFu this hydro-separation is done mostly with collected feints although it can be done on low wines.
In fact diluting the low wines to below 27% and allowing to settle before charging a pot still for a spirit run is recommended practice. Probably because it was traditional to use blended boiler charges with feints mixed into the low wines for the pot still.
However, for neutral or vodka, if you keep accumulating (and diluting) the heads and tails from previous spirit runs, and then only use the middle section of this to charge the boiler for a spirit run, over time the 3 layers get bigger. The top layer ends up looking like fuel on water. I used to do this early on when I was using the packed column a lot, but it got relegated to only used occasionally, and it wasn't really worth the effort.
If you make a lot of vodka - and mostly from accumulated feints from previous runs - then it might be worth giving it a go. It is a limited application, and probably is only useful to folks consistently re-cycling feints.
Not sure if someone later on already mentioned it, hydroseperation is professionally done at 17% ABV it only takes around 10minutes of resting at that low of an ABV. This will only work when there's enough heads and tails, i've tested it (and seen it quite clear) on a distilling course i've been giving last year.
This type of separation is done a lot in Scotland by whisky distillers, they separate the middle part and add it to the next striprun.. when they would just toss in all of it again they would simply end up with only (or mostly) heads and tails after a longer period of time..