Channel balance for 41 lb window

Hello,
I'm looking for channel balance for our windows. The balance is the 385 but our windows are just a hair under 41 lbs. I put them on a scale to weigh them. Do you make a balance that works for this weight or can I but the parts and reuse the channels and springs. I would need the tops, bottoms and the block and tackles?

I would need to replace 12 of these to replace them on all the windows

Thank you,

Will