thats actually quite a good question, one which i cannot answer unfortunately, though i have noted some helicopter types do not have their own SRM's so the millitary has created general practices manual for those aircraft, which covers the basics of structural general practice, such as fastner edge distances, amount of acceptable damage before repair or replacement etc etc. which is basically copied out of the manuals of other types and general knowledge of the "trade".
so, get hold of a 747 manual, and just copy the general structural practices chapter.. should cover everything in a lighty.. if its good enough for a Boeing, im sure its good enough for a lighty.