this is the only poster that i ever paid someone to frame, yes it was crazy expensive--especially considering how little Grant charged for this semi-custom piece of art. its held up beautifully and i don't regret it.
back to your question, i have many posters that i have mounted myself, and i've found most have a little bit of wiggle room, but ultimately it depends the actual frame if 24" frame really can fit 24" of poster.