Ply Gem T-Lock balance shoe failures

We bought an 8-year old home with Ply Gem windows. On many of the larger windows, the plastic balance shoes have cracked under the stress of the spring, causing the balance channel to spring up and stress or break the tilt sash locks (which are also plastic).

The failure of these Ply Gem plastic parts is consistent and predictable. We have a number of windows we cannot open due to the balances already being detached, and others which we elect not to open, because any movement of the sash is likely to result in the same breakage and failure.

Customer service at Ply Gem tells me there is one-year warranty coverage only. They recommend that I buy replacement balances from them.

1) Is it possible for me to use these replacement T-Lock shoes with the original balances?
2) Are these compatible with the Ply Gem shoes in terms of size and fit?
3) Is there any alternative to plastic (as I don't want to keep replacing these)?

I need to fix more than a dozen of these windows, so I am hoping to find an effective replacement part which is better quality than the original Ply Gem T-lock shoes.

Here is a photo showing one of the failed T-locks in the end of one of the balance channels. The channel width is 9/16" when you measure the open side, and a hair less than that when you measure the other dimension. Is there a way to use the 15-194 T-lock shoes with these channels?