Channel Balance

Hi, I can't find a ready to install match for this balance due to the bottom shoe. Here's the measurements-
15-001 bottom shoe
19-002 top
1/2 inch width
12 inch long metal frame
1110 stamped in it
Window weighs 5 1/2 pounds

Your series 351 is the closest I see but how big of a problem is going with that with the 15-002 shoe?

-Thanks for the help.