All very good questions which I'll try my best to answer
1- should you harvest when you first see Amber trichomes?
A- When the trichomes start to degrade this is when they turn Amber and this is when we see the CBD % fall. You want to try and harvest with as many cloudy heads as possible. Your trichomes will still turn Amber just like a traditional high THC strain as their is still THC presence and pure CBD trichomes also degrade(turn amber)
2-Any other variable you should consider?
A- Yes, you want to flush your plants very well before harvest, you want those buds to grow as much as possible to maximise end yield but I think you want to know the best way to harvest for optimal CBD %?
I have found that 48 hours total darkness before harvest will help those clear trichomes start to turn milky and stop the trichome degradation
3- How important is curing.
A- Just as important as with Any other strain. CBD, THC, CBG will all change as the flowers cure. This you will have to test.
Try some at say 3 weeks dry
Then let it cure a week and try more
Repeat this. This way you will find what works best for you
I hope that helps mate?
All the best
Mark..