Pella channel balance, number on part is 16C BSI FC

Thanks for posting! I've forwarded a link with a quote for (2) of the requested custom assemblies. Your channel appears to have a 15-194 1" T-Lock Shoe attached to the bottom of it, which is sold separately from the balance. You'll need to be sure to add this to the cart along with the balances when making your purchase. 

Take a look at video tutorial below as a reference for how to swap out the shoes.

I'm glad to hear you received them in a timely fashion! For an idea on how to install these balances, take a look at the video tutorial below, starting at the 3min and 14sec mark. See if this might help.