How much hill training are you doing right now? DO you train from HR? Do as much hill traiing in and out of the saddle to see how you react.

I try to remain as aerobic as possible while on the bike, I will climb out of the saddle when its too steep to climb but try to stay as aerobic as possible. If you recover quickly from high HRs then attacking short steep climbs would probably be fine, for the longer gradual climbs I think you should be able to spin comfortably if you are doing enough hill training at a comfortable pace and HR.

Its going to depend on how you recover after gunning those hills. I know for myself that if I blast hills too early my HR&PE is higher at all speeds thereafter, hence I prefer a steady effort rather than spiking it., but thats what works for me. If you train that way and it works don't change it.

It looks like a great race. Remember to grab the bidons wiht water and electrolyte, not wine when racing though :)