I use whatever's working...sometimes one or the other slows down, I swipe up my quick menu & switch to the other...seamless
I usually only have one of us search so others can enjoy the park, or be observant while one is busy. Also, it burns the battery in only one device at a time. I particularly like giving my device to a kid while I run for a restroom break. Gives them a task & I get 2 things done at once.
How long? Varies for sure, but I would say I can get something hard to get in an average of 15 minutes. Sure worth 15 min. in one line & a FP I want too.