I use 35mbps for 2.3k, 1920 60fps and 30fps. It's good enough for me.
I don't know why, I can't change the bitrate for 1280p 120fps and 848p 240fps. I tried 35mbps and 18mbps. it stays at the default values which are really low !! (between 3 to 6 mbps)
Does any one succeed to change these...