Just before they pip internally the air cell will pull down on one side and develop quite a slant. I'd keep an eye out for this stage (there's nothing wrong with having a quick candling check every day) and stop turning then. Alternatively you could turn them for a few more days then leave them. Turning is really essential for the first week and after that it isn't quite so important.
Candle the eggs and use a chart, such as this one:
https://www.backyardchickens.com/articles/development-of-a-chicken-embryo-day-by-day.72537/
or this one:
https://www.backyardchickens.com/ar...ion-through-incubation-of-chicken-eggs.47879/
to try and judge what stage they are at.
Good luck with them. Silkie chicks are so cute.