Finally I've found my second GPU with Samsung memory onboard... Gigabyte GTX 1060 Xtreme 6GB. Now my mini rig works in this way

GPU0 - Gigabyte GTX 1060 Xtreme 6GB (Samsung)
Power: 65%
Temp Lim: 69°
Clock: -40
Memory: +950
Fan: auto

Mine 25.5 MH/s @68° - Stable


GPU1 - Gigabyte GTX1060 WF OC 3GB (Samsung)

Power: 66%
Temp Lim: 70°
Clock: -30
Memory: +950
Fan: Auto

Mine 25.2 MH/s @70° - Stable

Now I would like to reduce a little bit the temperature. In which way it is better? Any advice?