With my mouth, my buckets have 3 square drainage holes, i suck the water out and spit out for 10 mins and she doesnt have too much water sitting in the soil i pull probably a half gallon. Its better with a shop vac but i currently dont own one..
One last tip to give you an advantage in flushing from the start, when you first pot your soil trench the soil in water until its heavy and moist and then transplant when medium dry this helps with good drainage from the start. So when you flush or feed water runs down great.
Rapitest soil meters work pretty well, but im not to fond of sticking bis ass needles in my soil.....
I seen your question about your plant being bone dry reason for that is simply because she needed water.....so you flushed the soil......which in terms your drowning her to flush all the salts...
Make sure you swirl the soil around man so she can breath and what I do and this is optinal I suk the water out my plants with my mouth on through the drainage holes, that's the love and care that goes into them and thy what's I recommend you do as well