I think they’d need to be first-surface mirrors. Here are some 94% reflective acrylic mirrors. They are not outlandishly expensive. The high end glass ones are,

I think they’d need to be first-surface mirrors. Here are some 94% reflective acrylic mirrors. They are not outlandishly expensive. The high end glass ones are, though. https://www.firstsurfacemirror.com/acrylic-first-surface-mirror/ https://www.firstsurfacemirror.com/acrylic-first-surface-mir...