I will keep these tips in mind next time. Looks like I need to do some research draining the pool.No need to retest, but in the future keep adding drops until there is no color further change. Don't count the last drop that didn't change the color. With the CH test, you may different shades of blue.
Yes. Drain as much as you can. A 75% drain will get your CYA to 50 ppm, a good level for a So Cal non-SWG pool. CH level will decrease from 1700 ppm to 550 ppm when refilling with CH 175 ppm water.
I'm not sure, but it should be okay?
Draining in the middle of summer can dry and crack the plaster surface. It needs to remain moist, but it's gonna take at least 15 hours to drain 10,000+ gallons (@700 GPH).
Depending on how high the water table is in your area, there is a slight risk of the pool shell popping out of the ground.
See the article on draining for additional info:
Draining - Further Reading
www.troublefreepool.com
I plan to use a submersible pump removing water from the deep end and filling from the shallow end since the water temperature is relatively same.
Can I do this across a week timeframe? The article indicates that the drain and fill should not be stopped until complete.