What oil i can use for hydrostatic bearings, at what viscosity?

i am doing a project in hydrostatic bearing, can any one suggest some oil that i can use for lubricating, and also i want to know the viscosity of the fluid?What oil i can use for hydrostatic bearings, at what viscosity?
The best oil for most 30w non detergent. It's the pressure that keeps them ( in the float). There are so many synthetics out their now. I'd have to do more research. Depends on temp.too. 10w 40w (10-4 good buddy)