Here are a few options for install using the L&D custom RAM rail. What differs is the adapter used to position the screen. I only listed the adapters that actually work, and only adapters that I could buy on amazon.com with free return.
First off is BRCOVAN double socket arm compatible with RAM Mounts B Size 1'' Ball (posted here before)
It position the screen higher, hides the mounting and the cables better, offers more support from larger area resting on the dashboard.
Takes away some of the visibility out of the windshield, and has a longer reach.
I do not have a picture with both screens for this one but see previous posts for pictures.
Second is VAZESWIN Double Socket Arm 3.5"
It positions the screen lower, offers good support from resting the body on the dashboard.
Takes away less of the visibility out of the windshield and has a shorter reach.
Relative position of screens:
Last is FANAUE Double Socket Arm Medium Arm – medium DA-90
It positions the screen lowest, offers some support from resting the nut on the dashboard.
Doesn't take away any of the visibility out of the windshield and has the shortest reach.
Relative position of screens: