Hi Charlie.
My iPad Pro has the slimline keyboard/case. I made a simple hinged mount with tabs at the top and bottom. The iPad with the case folded back simple slides in from left to right.
The mount is also hinged so I can access my 2 x CPI's behind it.
As iPad models change, I simply make a new slide in mount, this is the first time I have used the 12.9" Pro and I like it a lot
I'll take some photos when I am back at the hangar.
Original 11" iPad in solid rain,
