I have the same steering.... I use a right angle flat head to get mine off.

I leave the top plug in and fill from the bottom up all the way to the reservoir.

Using a 5 gallon pail with a pail pump helps with less air bubbles from changing bottles.

Remove and clean the reservoir.

+1

I use this pressurized gear case filler. Makes it go pretty quick. The moment I see the oil start to enter the reservoir, I release the pressure.