@zacland
Sorry for the delay,- I was on holiday B-)

Are you sure you're running the x64 PC-Version of Recalbox? I verified the option is still there in the latest version 8.1.1: In Mame OSD you should see the list of games, directly under that list is "Configure options" Once selected, a small window opens with several options and "Save configuration" at the bottom

Good luck!