Need a quick answer on mouting aesthetics (6x7cm neg into a 20x30 print)

I have a portrait orientation landscape I'm printing, the print format is 20x30 as is the frame.. should I just matte it pad the top and bottom with black and mount it like that in the frame? I don't think there is a ready made frame size for cutting the print down to 20x24 and mounting it in that etc.

Will it look like crap in a gallery with the black bars top and bottom in portrait orientation?

Mount on foamboard instead?

Cut a sheet of foam-core slightly smaller than the print,then bend the print over the edges of the foam to cover it, just hang like that.