If you are really interested in bridles, Andy Wardley has written a very informative dissertation on the dynamic bridle. He's the bridle guru, who developed the bridlles for the Benson Gemini and a number of other kites.
The address is http:/wardley.org/kites/bridle/dynamic.html
In the art/science of bridle-making there is a degree of trial and error
which can be aggravating. In the building process, keep notes on what you did and how well it works in order to got back to a successful adjustment.
This is a generalization and also may be used as a starting point: When you pick a kite up by the bridle pigtails. the spine of the kite should be level horizontally.
Also remember, that all lines for the right side (wing) of the kite should be EXACTLY the same as the left side (wing), as nearly the same as humanly possibly.