I did my service today. I tried the pump and was only able to remove about 4 gallons. I removed the drains on each side of rear axle one at a time and was able to control the flow without making a mess. These were 14mm bolts. I drained my oil pan after each one. There's a larger drain, 24mm, that drains straight down. It was easy to screw the drain back in and empty my oil pan. It contained most of the fluid. I had to empty it twice on this drain plug.
I think next time, I will skip the pump. It's not as bad as I thought it would be. The filter had almost no fluid when replacing them. The total for filters and hydraulic oil was $690. This included an outer air filter and a fuel filter.