Thanks to Bob and 81X for the time to do such an illustrative post. Very helpful.
At this point, still kind of experimental, I've mounted the iPad mini 5 onto the co-pilot yoke (with a Ram yoke mount and "long" arm) so I can swivel the iPad towards the pilot better. It's only a half-arm length away and easy to pinch to zoom or expand, or to change screens).
My second plan was to mount my iPhone X, regular size, onto the pilot yoke with a similar Ram mount. It set up GREAT, to use the iPhone for more data info items such as frequencies, metars, taxi diagrams, etc) with the iPad mini being used for for moving map displays and other real-time navigation depictions. The only problem is that with my short legs and the need to scoot the pilot seat forward a good deal the iPhone is actually too close to be comfy and cockpit movement bumps into the system. So for now I'm back at the drawing board on the second EFB. The side window is so situation that I haven't been able to figure out a suction mount option but I'm still working on it.
Thanks, all...