You can use a separate emunand for sx os atmosphere. That's how I was setup at one point. You need to create the sx os emunand first then you can resize the fat32 partition leaving the correct sized partition unformatted as the last partition. You can then use emutool to restore either a nand...
It works no different using sx gear and a chip and you don't risk bricking your chip by flashing a firmware that wasn't really made for it and hasn't gone through a whole lot of testing.
He made similar comments when SX OS was released and he got nowhere. He's just a big baby that believes everyone should worship him. It's quite pathetic.
Plug your switch into a pc then double tap the backplate to push the button on the switchme chip twice. A new drive should show up under my computer. Drag the sx os uf2 to that drive and drop it. The drive should disconnect then reconnect. Unplug it and try to reboot...
Read through the forums. Most posted needing help are with atmosphere users. SX OS works and you don't need to jump through hoops to get it working properly.
Just drill out the head of the screw then you can remove the side rails and grab the rest of the screw with a small pair of wire snips and turn it. make sure you don't get metal shaving s on your motherboard.