i get away with 20-30% without too many issues on regular injectors as long as i run cleaner and go to straight diesel for a tank or two when the idle starts to chop or i get idle smoke. thats with atf,wmo.
good light hydraulic with my modded injectors would run fine with my mechanical pump at 100 percent if its warm enough.
if you can centrifuge it, its a viable fuel at 40-50 percent with my mechanical injection pump. not so sure with the ds4 pumps.
your pump has an optical sensor if its the ds4 electronic type.(unless you have a mechanical ip now) if the hydro fluid is fairly clear/translucent and you can get the water out and filter to at least 5 microns i would not be afraid to go 20-25 percent mixed with diesel and do a periodic injector inspection to monitor for build up.