Oh,.. wait,.. that machine takes the 2 part bobbins, right? The ones that don't have a hole in the middle?
Argh,.. no, a side winder wouldn't work for those bobbins.
You might have to get that bobbin winder working.
The tension spring for the upper thread? It should sort of hold a little extra tension on the thread when threaded correctly. It does seem a little loose when it's just sitting there.
If I manage to get into the sewing room tomorrow, I'll thread that one up and snap a pic for you.