I am planning the extract version of Theakston's Best Bitter from the British Real Ale book by Graham Wheeler. While, he doesn't specify the addition of any cars-pils, I have read that it does not effect the finished flavor, but significantly aids in getting a decent head on the finished beer.
The book recipe calls for 4 lbs 5oz of DME and 6.2oz of crystal malt.
So, if I were to add some cars-pils, I estimated 2.8oz. I think this is around 4%.
Any suggestions about this? Has anyone brewed this recipe as an extract? If so, what did you think of the finished beer?