My rear wheel needs to be rebuilt and I am trying to decide between going with 14/15 double-butted spokes or plain 14 gauge spokes.

I'm having someone build the wheel with a Sun Rhyno Lite rim on my old LX hub. I weigh about 210 and this wheel is going on an aluminum hardtail, so wheel strength is far more important to me than saving a bit of weight.

So the question is, which makes for a stronger wheel? Does the added flex in the double-butted spoke really result in a wheel that is less likely to break under a sudden load or does that flex just fatigue the spokes (or is it some of both).