That way we can book to windows using exit to refind, and exit to GRUB UEFI for ubuntu.
You are on the right track on the other thread. The two refind options are what you need. This way you can target where refind looks for the boot files. You can include and exclude file paths to get what you need.
The grub4win implementation inside fog is bios only. BUT that’s not to say you couldn’t use a similar concept to the dual refind hack to leverage grub too. There are a few ways to go about it. I don’t have to deal with dual boot so I’ve never looked into streamlining that flow.