I do exactly what Clive describes except I take a guess at the contrast I need (nearly always grade 3 plus or minus one) and adjust from there. I use the midtones to judge exposure (since they stay the same-ish across contrast grades) and adjust the contrast to get the blacks and highlights I want. Test strips really aren't going to tell you the correct exposure and contrast, though. It only gets you close. When you see the image as a whole, you'll likely want to adjust.