Constant Force Balance Coil

Swisco Customer Service,

I'm hoping you can provide some assistance with my search for replacement constant force balance coils for my windows. My coils have no markings or stamped imprints, so here's a description:

They look very similar to the 190 Coil Balance Spring series on your website (single "shoe" attachment hole, "squared" edge)

The window weighs 24 pounds

Each "shoe" holds two (2) coils - so, four (4) total for each window

The width of the coil is 1/2"

The internal diameter of the coil is 3/4"

The window is approximately 36" long, so the constant force balance coil should be approximately 35" in length. So, I think I need 6 lb, 35" long constant force balance coils ... a total of four (4) for each window. Correct?

Does Swisco sell such coils?

Thanks!
Cheers,