I've been making Norwich sourdough for quite some time and really enjoy it's tangy flavor.  Particularly after I followed the tips from this forum at http://www.thefreshloaf.com/node/1040/lesson-squeeze-more-sour-your-sourdough.  [1]

Recently I picked up a copy Tartine and tried the basic country loaf. I was really happy with the oven spring, extra crispy crust and crumb with huge holes.  Which, BTW, I baked on a preheated stone with an aluminium turkey roaster lid since I didn't have a cast iron cooker.  However, the taste was a little mild for my liking. 

So, now I've been trying to come up with something that combines the tangy flavor or the Norwich recipe and the crust and crumb of the Tartine.  My first attempt was to use the Tartine recipe, but substitute 200g of my full strength starter for the 200g of leaven.   This gave me the flavor, but not the oven spring, crust or crumb that I was looking for. 

So, I'm looking for suggestions for how I can get more flavor in Tartine recipe while maintaining the crust and crumb?