i think if i was forced to choose between spending £9 on a wheel building book or £10 on some new spokes/nipples i would go for the new spokes.

good wheelbuilding advice is freely available, it's not rocket science even numptys like me can do it after looking at the sheldon/park website.

(i took the wheels to my lbs who looked them over with their dt spoke tensionometer thingy. they said they were well built with even tension)