I do agree that most of the climbs are long and medium in gradient and can be spun up with the right gearing. I was just under 9 hours on my first attempt with a few cramp problems and some leisurely food stops also doing it solo.
Last year I was about an hour quicker due to riding with a buddie being fitter and really pushing on a full gas for the last 3rd from Princetown back to the end.
I have entered again this year and would dearly love to try for a silver time which I think for my age group is 7:20 which is going to involve a good bit more speed and very fast food stops. We will see how the training goes.
I personally find the typical dartmoor classic climbs much easier than the short steep climbs that can really take it out of my legs and it is an exercise in eating and drinking enough. As well as enough training rides to be comfortable on the bike for that length of time.