Of course there are general rules. Wheel building isn't rocket science, it's more of a craftsman + specific knowledge kind of thing. A wheel builder will ask a customer questions about riding style, weight, terrain, and budget and translate that into a set of wheels. The information can be organized in a matrix. Psimet appears to make part of his living doing this so maybe he's reluctant to share his knowledge, but his customers are unlikely to be do-it-yerselfers who'd rather buy from someone. I've built a number of "sturdy" wheelsets but am interested in testing the limits for a lower weight set, thus my question.

I'd also like to hear why butted spokes are more durable than straight gauge. I've switched to straight gauge for the last few sets to save money and haven't had a single break.