[wwittman]

The trimmers on the HD interfaces don't have ENOUGH attenuation to make a substantial difference (in my expereicne) if someone sends you a screaming hot session.

I would do ALL those things:
recal the output
turn down the trims
and pull the whole PT session down by 6 dB or whatever it takes to make the level to the desk seem sensible.

You don't want to cream the input front end of the desk... turning it down internally after that doesn't solve that problem.
It's just not a nice sound.

In these 24 bit days, pulling down all the PT faders (by grouping them in 'ALL') doesn't seem to be a problem.
And it's a much better solution that slamming your desk.