Some answers from a European, maybe they are helpful, if not just ignore.
What I like about a rally is that its difficulty and toughness is increasing during the days. Start with simple navigation and not so long days and increase it to a maximum one day before the last day. Very technical part can be put in a liaison section, preferably not in a special because racers tend not to take time to find there way and damage their bikes.
When the Tuareg rally still was held in Maroc it used to be like that. First day a technical part called Enduropath in the Liaison to distinguish the profi riders from the amateurs (changing classes still possible). And on day 6 and 7 a small technical part also in a liaison called Boilerpass and the Alex Kante pass.
Long days are nice when they are alternated with some simple and/or shorter ones. In the Albania Rally 2012 there were 3 days of 450km+ (11 h in my case) alternated with shorter days or a rest day (which I did no like).
Navigation should be demanding enough to prevent very fast driving, this distinguishes a rally from a race like Baja. This year's Hellas rally was really simple navigation, just follow the main path most of the times and the driving was really fast.
More answers to your questions:
1. 6-8 days of racing
2. 8-10h a day
3. Navigation should be more important than speed
4. I like technical parts but it should be doable on a bigger bike
5. Start with a small and simple special and increase its difficulty and length during the days.
6. Bivouac, I do not need any luxury.
7. Minor, <100km in the morning, <50km in afternoon
8. Moving bivouac, more changes in terrain possible.
10. Learn them to like navigational challenges above full throttle
I hope this helps a little.
FE570; CB500X; KLE500