I just leave the settings the same between Rift and Odyssey, with the Pixel Density set to 1.5 and SteamVR just left at 96% - sort of explained why here 
fpsVR - #3 by fearlessfrog
Here’s my DCS settings - Our Samsung Odyssey (+) first impressions, tips, and tricks... - #176 by fearlessfrog
For X-Plane, I just plain SteamVR 160% it and use the excellent 3jFPS util to manage frames. At CYVR with some traffic in the 737-800X I’m about 30 FPS, with more comfy frames at height - X-Plane 3jFPS Wizard for VR