Could you rest a siddur (large or small) on the back of the bench and use a magnifying dome? That one is small, 2 inches, but 8x magnification, but Amazon has them at 10x and even 40x magnification if the 8x does not make the text large enough for you.

The smaller item would be easier to carry, but many shuls have little storage cubes for people to leave their tallis and teffilin bags, and you could probably leave the magnifying dome in your cube (if you have one).