The screws are a problem at this point. I do know that the same screws that hold the throat plate fit the hole - they just aren't long enough. I'm working on that part but not getting very far. It may have to have new screws and then be tapped to fit the new screws. The first machine got lucky - I fished stray screws out of the miscellaneous box of screws I have laying around. But they were the only ones I had.
Let me clarify this some more. The motor mount screws you removed will NOT hold on the belt guard/bobbin winder. You will need 'new' screws of one kind or another. That will be the biggest problem doing this conversion.
You will also need a non-geared wheel - the potted motor wheel will not work anymore - well it would work but it would be nicer without a toothy grin...