This is the biggest thing I've learned, don't trust anyone but you and the recipient to care about the package, no one does and they will treat it as such.
I will be sending door glass to the UK, and I know no one cares but me and the guy getting it. Delicate, you bet. I'll pack it in a box inside another box, with packing to coushin the glass, and also to coushin the other box. It's all up to you.