Uncertain of channel balance

I do not know exactly which channel balance I need. I would like a brand new complete unit for two windows. The windows are located in bedrooms, they are non-tilt, the current channel is 1/2 inch. The length isn't quite 23 inches. The windows are pretty heavy, I don't have a scale to weight them though. The markings on the channel read 22 5 B0 CALDWELL.

Thank You

Matt