Hey there! Thank you for reaching out to us. The pivot shoe shown here isn't made anymore but you can use the 15-177 to replace it. You can also reuse the old springs if they're in working order.
We'd be happy to help with the pivot bar but we would need to see photos of it removed from the sash to compare to our inventory.
Our 26-226 looks like a good match. Have a look and see what you think.
For the 21.5-pound sash, you can use one S152-5 and one S152-6 on each side of the window; 11 pounds of support on each side will total 22 pounds of overall support.
For the 18.5-pound sash, you can use one S152-4 and one S152-5 on each side of the window; 9 pounds of support on each side will total 18 pounds of overall support.
Let me know if you have any questions!