Personally I think bigger is better for two reasons first if you're gone to be doing photos or videos the larger screen gives you that much better view into the world around you. Second if you want the brightest screen the iPadPro 9.7 has the brights display in the entire line up at 500 nits.
As fast as use the Cadillac for holders is the MavMount and it's built light weight but like a tank bing made out of aluminum. Anyway here's a review I did a few weeks back.
Good luck!
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