Yes, that's true, the 80cm passage will be difficult to manage, I have already noticed that. And with 1m of drywall at the shower corner, the water will probably splash into the passage anyway. An approach would be to stick with the T-solution, allowing the 80cm passage at the toilet and an 80cm drywall (so a 1x1.6m "seating area") and the shower will also have an 80cm passage with an 80cm front wall (also 1.6sqm). The passage at the shower will be closed with a glass door, so the shower space can be used more generously and the rest of the bathroom stays dry. Nevertheless, we will keep the shower at the window.