Normal for most of our engines including the DLE60 is 28 degrees BTDC. A degree or two one way or the other will have minimal effect on how the engine runs but I like to see not less than 28 and not more than 30. This is measured and the spark is triggered just as the magnet passes under and away from the sensor when the engine is turned in the normal direction. There is a video and good information at ...
http://www.rcextremepower.net/timing.html
I would recommend the available audible sensor tester and degree wheel. This is easier than watching for the spark at the plug.