There shouldn't be much of a difference, I was just saying that our springs are attached to the screw differently.
As for what strength springs you need for your window, I can't really say. There is no standard bathroom window, they all vary. You will have to weigh it and see what it comes up to.
Keep in mind that coil balances are different than other types. You would divide the sash weight to see what strength coils you need. For example, if your sash is 16 pounds, you would need two 8 pound coil balances.
Got it, Thx! This was very helpfull. I will be placing my order asap.
Mike