mille cymru gearing for climbs

[montage]

Basically, this takes in most of wales - 1000km.
I come from a road racing background and as such this will be my first audax (yeah I know...) - what kind of gearing is needed for the climbs in wales?

My plan was to stuck a 12-30 on the back of my bike, giving me 39-30. How does wales compare the the steep climbs around the Trough of Bowland / Yorkshire Dales?

I can stick a 50/34 on the front but it'll cost a fair bit

 

[raleighnut]

Think in terms of Hardknott/Wrynose kind of gearing.

 

[Pro Tour Punditry]

You'll not just have to consider the gradients but the cumulative effect of several 100s of kms., even relatively easy climbs can seem insurmountable after 20 plus hours in the saddle.

 

[Ian H]

As Marmion says, consider the gear you'll need for climbing when knackered.