Here's what I've finally decided to do. I'm going to buy a 21' piece of heavy duty channel (b/c that's the only length my metal shop sells it). I need a lot of the channel for making some 2' gauge locomotives for the (buffers) bumpers where the link and pin go. There will be enough left over for the shop press.
In the meantime, I'm going to straighten out the C apron with a rosebud and flip it over and use it until it fails. If it fails, perhaps due to undetected stresses on the steel from the collapse in four places (the only visible damage), I will use the pdf Jim sent as a blueprint for a new apron