I don't have any specific tips, only general. There is no "best" way to mike an amp. If you read Guitar Player (and probably the other mags) they often ask about studio setups in interviews. Some of the producers use close-miking, some run direct through a direct-recording tool (POD, etc.). You might try running two mikes - one close and one far AND run direct into another track. Then you might be able to mix the three sounds into something you really like.