If you have not do so tilt the seatback away from vertical. Sitting on the seat with a vertical seatback puts more pressure upon the tailbone area. You can also tilt the nose of your seat. Use a shim under the seat frame. You could also add extra foam under the seat cover. These three (3) solutions
have helped me in the past on some of the "Bents" I have owned. GOOD LUCK!!

Carpe Diem