Replacement parts dual coil constant force balance

Hello, I'm trying to identify proper replacement shoes for dual coil balances. I've attached photos and an OD tag on the window which are double hung tilt windows. Also trying to determine best way to remove balance as the is only an access in the middle of the side fram and not at top. I know I can cut in access at top of side rail but wondered if there was a tip to getting out of existing access spot without causing damage.