I find that a piece of wood under the front of the seat helps with the angle and is much more comfortable on a long trip. A bit of 45mm square under my seat forward edge and another smaller section half way back to support the middle works well for me. Longest single trip was just over 500 miles in a day from Germany back to Lincolnshire. A short break for the tunnel was good, worst part of the journey was the M25, as always.
