Gans Ink makes a Snow White Opaque ink for letterpress. It is a specialty color with intense pigment. That said, it still does not give a true pure white base to overprint on but it may work. After printing the white you may need to double hit the teal. The additional issue with a teal ink is it may contain transparent white which does no help the color body blocking show through. Good luck.
It all depends on how red the paper is and how light the teal is. I would do a first pass of opaque white, then a second pass with the teal.
Gans Ink makes a Snow White Opaque ink for letterpress. It is a specialty color with intense pigment. That said, it still does not give a true pure white base to overprint on but it may work. After printing the white you may need to double hit the teal. The additional issue with a teal ink is it may contain transparent white which does no help the color body blocking show through. Good luck.