It's minimal help, but after combing Sear, I find that the reverse looks a lot like another reverse (SG6895) that depicts Seleukos II. SG6895 is AV, so this is only useful for a further description of that Apollo: naked Apollo standing left holding arrow and resting on bow. If you look for an AE12 or AE13 with that reverse, you may get closer to an ID. The obverse looks so far off center that all it got of a bust was the locks of hair, which as you have experienced is a serious complicating factor.