Everyone has a different idea of what's best. In my experience, anything 62g and lower can hang on the return, even when lubed. Since springs become softer over time, this can become a bigger problem. When I've used 65g springs, I had no problem getting a nice snappy return each time. 67g springs, IMO, are the perfect spring for clears, but they're too heavy for some people.
In short, there's no such thing as a perfect spring. You really just have to try different ones and see which one works best for you.