From the mfg's home page.The normal method of recurving engine load ignition timing is to set the no load (high vacuum) timing at an extra 15 degrees over the mechanical (RPM) value. Then just use a flat line for the rest of the values, down to full load (0 vacuum). ie 5 degrees extra for about 6 inches Hg, 10 degrees extra for 12 inches, and various points in between. Then when you drive around note the RPM and vacuum readings when you hear pinging, trim these values down 2 or 3 degrees in the map, and retest. If you have no ping, then try bumping a few values up to get max output.
I love tuning. Makes a huge difference.
Hope it helps.