I'm not sure how easy it is to remove and replace the bobbin case on a 201.
There's pictures of the bobbin case removed nearly at the bottom of the page.
http://oldsingersewingmachineblog.co...-later-models/
I'm not sure how easy it is to remove and replace. Usually drop in cases aren't meant to be taken out all the time.
I would just adjust the tension as needed. It's probably easier than switching the case out. If I was sewing with thick thread often I would set up a dedicated machine.
Singer made a 4 legged electric cabinet with a top that looks like a treadle cabinet. It could be you have one of those.
I think you do have the right tire on your winder. You just need to take a few seconds to adjust it.
Rodney