I think we will be using an open air frame setup, but I know I would take the 35 db fans at 63C over the 60 db fans at 56C every day.
On GTX 1060 the quieter fans are fine for cooling but I think on 1080's or Vega 56's the only option is to go with high power ones that are loud. I am still waiting for my shipment of 1080TI's to arrive to do some testing with them.
Quieter fans please without sacrificing too much heat. If you do manage to get a Vega or RX580 for testing can you undervolt them (most miners will do this anyway) and see what temps you get?