Need help to identify hardware for two different windows

Thanks for writing in. The tilt window channel balance appears to be an S775-28. For a stamp option, choose 28B; for the shoe size, it appears your balance's wedge shoe is 1-1/4" wide, but pictures of measuring tape can be deceiving, so please double-check to be certain. 

For the non-tilt channel balance, I need a clearer picture of the top nylon fitting. Can you send a good picture or two of that top attachment? I'll do my best to fully ID this balance from there. Many thanks. 

Perfect, thanks. This non-tilt window channel balance looks like either our S351-29 or S390-29. The only difference between these two channel balances is the depth of the bottom nylon shoe, or the 'heel-to-toe' measurement. Compare the diagram below with your old hardware to see which matches best. For a stamp option, choose 2820.

Comparison of the S351 and S390 balance shoes.