Best timing to use starter

I am a newbie and have created my own starter and have had some good success so far making some basic breads.  One thing I am trying to determine is the optimal stage at which to use my starter for a new recipe.  So far I have been using my starter to create a new dough several hours after the latest feeding and typically waiting until it has at least doubled and sometimes longer.  I have however, had varied results as it relates to the rise of different loafs (some flat and some very full).  My theory is that optimal timing is probably when the starter "peaks" after the previous feeding assuming this is when it most active.  What are others theories or is there a specific rule?

Thanks,

Crustic