Hello Rain, Very good video!
I find it's always easiest to remember to put a Singer washer back in with the writing facing inwards. Also I make sure I completely remove the small screw and put it in a safe place before removing the stop motion screw itself - if it dropped out I would never find it on the floor. Another handy trick is that if you have a spoked wheel you can look round the back when you have put the stop motion screw back on and you will see if the small screw is in the correct position in relation to the projections on the washer.
Now I'll show you my naughty Serata where the wheel is stuck fast to the shaft. The cocktail stick shows the lubrication hole. The end of the shaft is completely flush with the centre of the wheel, so there is no handy groove for the washer to sit in, as on a Singer. Therefore the two little lugs in the middle have to point inwards, towards the machine, the opposite way to a Singer washer. The other side of the Serata washer is completely flat.
Now you see my predicament and why I am more or less resigned to letting the wheel stay as it is.