Here’s another good link
US Car Tool A518 Cross member
It shows how the upper crossmember can be left in place and fabricated to remove enough material and be refit to have enough clearance. This is what I did but lots of guys have just cut that section out and replaced it with a good fitting curved piece of flat stock. Doing it this way definitely gets more clearance. Not sure which way has more structural strength but I think it might be just a personal choice. I don’t know where you can get anything premodern to fit the unelected like the lower but you can probably have it done locally if you make a template.
I’m sure you’ve done lots of searches on the google by now. Lots of pictures and info out there to help.
