Hi Sailerkid,
Before
rerigging my Ingrid I took Brian Toss's
rigging class. He explained rig design to some degree and goes into it in more detail in his book- "The Rigger's Apprentice". The basic design criteria starts with righting moment at 30 degrees (at least as it was explained to me). The force to heel your
boat to this point is easy to calculate and gives you the starting point for load calculations. Of course the other way to go about it is to find a sister ship that is out there sailing...
Good luck!
John