The "gravy" color of your hydraulic fluid means the system is still dirty. That's why a kerosene flush is so very often recommended. Clean hydraulic fluid should be so clear, that it's difficult to even see on the dipstick.
AW32 has the viscosity equivalency similar to that of a 10W engine oil. Then the higher the number, the thicker the fluid. AW46 and 68 are in the 20W range, AW100 moves into 30W territory, et cetera.
But many folks in cold country have found that using anything thicker than AW32 requires too much warm up time before the steering and hydraulic work. I say this, because many universal (THF) fluids are very often in 30W territory.
//greg//