Front Bumper Bolts Torque Spec

[OldChargerGuy]

Hey, Ghoste.
First, your Inbox is apparently full. I hope you're still breathing.

I just saw an old post in which you shared detailed torque specs for front-end chassis parts.
How about the front bumper assembly of a 1966 Charger? Specifically, what is the factory torque spec for the nuts of the bumper bolts, the bolts with rounded, chrome heads that are exposed when assembled?

I have the '66 Service Manual and Charger Supplement, but no luck finding torque specs for this part.
You guessed it . . . a freshly chromed bumper was cracked during installation. We are trying to determine why the new chrome finish cracked.

Thanks for any help you can share.