IMO the Pyramid is not a real good example of a fruit beer. It has no fruit taste just an aroma, so you think that you are tasting it but really your not. I took a tour there a few years ago and was talking to the person giving the tour and he said tha they use an extract in that beer. I feel that there is a world of diference between using extract and real fruit.
If you are talking about making a starter and adding it to your primary, you are going to loose all the fruit flavor and aroma by the time that the beer makes it to the bottle/keg. Good rule of thumb is one pound of fruit for every gallon, and put it in the secondary for a couple of days just long enough to puck up the flavor and aroma, but not so long that it all ferments out. If you decide to go with the extracts then you can add it right before bottling/kegging.
Cheers
