Don't forget that in the summer heat....the third option.....Darwin Adventure Gear can be very comfortable..... Kindly demonstrated here by ex Mr Lozzy
All I can add is that from my own experiences of going walkabout on the track a number of times at indecent speeds I want as much cow as I can get between me and the blacktop, friction burns are pain, but the alternative is unbearable, so a vote for decent leathers, and 1 piece all day long. On the road it’s a mix of textile and cow.