A Zone I density of 0.1 is really just a starting point. If you can get enough shadow detail that way, then you'll get more room to play with at the highlight end of the curve, and the thinnest acceptible neg, which will also be the least grainy. If you're not getting enough shadow detail that way, then it's reasonable to increase your working EI, but keep an eye on the highlights, to make sure you're not losing anything at that end of the curve.