1 mg/litre NAA in MS2 medium should be fine, make sure you have nice sharp stem cuttings with a healthy young apical shoot (small leaves), it is extremely important to have neat cuts using a sharp scalpel and using a sliding motion, rather than chopping (and crushing part of the tissue). It can easily take 4 weeks before you see roots, so don't loose heart. The 100% humidity in the sterile glass jar keeps the plant alive, even if you don't see any progress. Do many of them so you have more chance of success.
For rooting of most plant species, IBA is recommended. The rate of application, however, depends on the age of the cutting (softwood, semi-hardwood or hardwood) and the nature of the plant's response for ease rooting. Most importantly, for coffee you should be very careful in selection of branches. Normal and healthy plants are mostly obtained from rooting of orthotropic branches as compared to cuttings taken from plagiotropic branches.