For accurate tuning you need log OBD-II drive time data, then, analyze that to give you meaningful average values. The most important of these data is you trip average O2 sensor value. Generally, if your value is greater than 0.45 v, then, you need to lean.
I use Carchip from Davis to log my OBD-II drive time data. I configured it to log RPM, O2, MAP, Load. I use OBD-II Easy Viewer software from greenfuelbooster.com to analyze the data . By balancing leaning AFR and HHO boosting I got my 2006 civic lx get 48MPG highway average.
Since my civic has really tight space, I use a compact HHO generator also from www.greenfuelbooster.com