White's Reality Check is the best. A system that survives that test really has an edge.

WRC is unfortunately impractical when you manually develop a system. It can be used when a system is developed solely by some mechanical process, without any human intervention or pre-selection. That's what I'm currently attempting on the "Financial Hacker" blog.

But for normal system development there is no perfect solution. The best is a combination of WFA and common sense, i.e. using only rules that are rational and exploit a real inefficiency.