Having used a pair of 15.6" screens for over a year, I can completely back up Sling’s point. You lack real estate. On top of the touch screens, I was also using a pair of tablets with SpaceDesk to add extra real estate for Air Manager. Particularly on the more complex planes like the CJ4.
I’ve since upgraded to 22", and it’s basically a night and day difference. I still use one of my 15.6" screens in my setup as a pedestal / console for planes that require instruments there. But now, pretty much everything fits just fine on my 22" screens.
A few examples of what you can do with Air Manager and a couple of nice size screens:
C310R:
C172:
C414AW:
