Orbit Position
Got it! it is a mistake that I take the enemy bearing as orbit bearing, again ;) Now after switched to orbiting the fire position, the score against RaikoMicro improved a lot ;)
However, there is another bug that hurts a lot when I fix it ;(
From what I've seen, most bots orbit the enemy location. Perhaps what might be useful is predicting the enemy location with your gun, then orbiting the predicted location in your precise prediction? DrussGT does something similar to this, although being a GoTo-surfer it doesn't work this way exactly.
I think something like this is really important for a GoTo-surfer, or you'll have to update GoTo location too frequently to match new information. IMO, however, a True-surfer can update gradually to smooth the effect of out-dated enemy location, but predicting still helps.
Now I'm orbiting around fire position while distancing on real time enemy location, in this way the result may be something between orbiting enemy location and orbiting fire location, say, when the distance to enemy kept good, it orbits fire location to maximize MEA, and when the distance to enemy is bad, it tries to adjust it gradually.