Grand Canyon flying minimum altitudes I'm looking to visit the Grand Canyon this September. I fly an open-cockpit two-seater gyroplane - a Magni M16. Its ceiling is around 13k' and I'm not wild about trying to reach the top end of that. I'm confused by the SVFR rules on the special Grand Canyon chart and would appreciate some clarification. 
If I look at the chart on Skyvector, I can see the allowed corridors and the SVFR area fine. Looks like in the east it's more restricted and for the Native American areas, you have to be above 14.5k' to fly over them (which rules them out for me anyway) but that I can use the Dragon and Fossil Canyon corridors down to 10.5k', which should work. The rest of the area I need to be at least 10k', at least over the Supai and Diamond Creek sectors. 

So far so comprehensible. However, in the west, you have to avoid The Sanup tribal area below 8k' but then the rest of the area is either the same or higher than that! Do I have that correct? Looks like I could depart from 1G4 and fly due east over the Sanup area at 8k', then turn north and provided I followed the edge of the Pearce Ferry sector, I could stay at 8k' all the way to the Bar 10 airport 1Z1. Is my interpretation correct?  

Thanks for any help and guidance, especially from anyone who's done this in a low power open-cockpit craft.
The rules for operations in the Grand Canyon Special Flight Rules Area (SFRA) are governed under 14 CFR Part 93, Subpart U.

Please review these rules here and all applicable GCSFRA NOTAMS prior to departure.  Also perform your performance calculations for the predicted density altitude on the day of your flight to verify your aircraft will be capable of ascending to at least 9500 ft MSL, else it may not be legally or physically possible to make the flight.

For an eastbound flight like that departing 1G4, I’d recommend a takeoff and climb to 9500 ft MSL (eastbound VFR altitude which meets the minimum requirements of both the Pearce Ferry and Diamond Creek sectors of the GCSFRA) prior to overflying the Pearce Ferry sector enroute for 1Z1.  Be advised for both fixed wing and rotor wing aircraft over the northern sections of the Pearce Ferry and Diamond Creek sectors.  Commence your descent into 1Z1 only once clear of the northern edge of the Diamond Creek sector.

Aside from the legal aspects, keep in mind that you are going to be flying over some pretty rugged country out there.  Have a plan of action should an engine failure or other inflight emergency occur enroute, requiring you to set the aircraft down somewhere.