OTOH, why the spying concern? In a Japanese spa or Finnish sauna, everybody goes naked, male and female alike. Tear down the walls! Bonus: You could play card

OTOH, why the spying concern? In a Japanese spa or Finnish sauna, everybody goes naked, male and female alike. Tear down the walls! Bonus: You could play cards with your neighbor. If the toilets faced each other, you could balance a chessboard on your knees and theirs.