I'm here again XD, I've found out that x264 custom presets would not be there if this thing is not checked:1.png
So make sure you have selected "show advanced options" first before you are applying a preset... I guess XD
It can be solved by adding a line to automatically enable this option if its not on.
And just saying that I've updated the preset thread, there are speed improvement, some other parameters are tuned, and added more presets