Thanks for the replies…I agree that the last setting is not great as the angles of both legs are 90. I am not sure which one to go for out of the other three – I guess it will be down to comfortableness.
I will try to get a video posted up to show the first 10m or so because I agree that you have to the clearance to make sound judgement on block settings – something I mentioned.
Can anyone else give an opinion?