How good should one's riding skills be to be able to qualify?
Edgar, riding skills is only one of a number of criteria that the marshals are looking at. It is not nearly as important as many might believe. I would rate the following as important: teamwork, functioning under stress, positive lookout, sharing your experience and knowledge, etc etc (I hope you get the idea)
The organizers also wants the participants to learn out of the experience and "walk out a richer man".
Many people has asked me to explain the Honda Quest experience to them. It is much bigger than what we think and although it is impossible to sum it up in one paragraph this explanation nails it pretty accurately: