Thanks Paul, I was hoping for someone who'd gone through the same process to give some insights.
It seems there is no answer that really maintains the flat matte look, then.
I'm aware of the color casts involved with AR glass, mainly from an angled view, but its still pretty amazing. Think lens Multicoating.
I saw a show a few years back of a (very respected) artists work, and they'd gathered all the pieces from a famous series together, all framed with AR glass, but of different types/generations, like Denglass, TruVue, GrossGlass, Schott etc. Every single type had a different hue: Purple to Green. It was very distracting when trying to view the work.
Varnish/ Print lacquer. Can't really do that option either. The museums I sell to insist pieces are glazed, plexi or glass, but must be protected from the public, and their fingers, fizzy sodas and sneezes!