Emerald Master, IMO the Gold Tower symbol is the hardest to get. So don't get discouraged, keep trying!
In other news, I just read that there IS in fact an Explosion Move Tutor in Emerald which made me happy, so now I can get a good CBMetagross, because I'm quite sick of my CBSalamence's screaming weakness to ice. Also, I tried my luck at the Battle Pike last night and I lost at room 75 to an Electabuzz. ;_;. (Electabuzz knew Cross Chop, Ice Punch, and Thunderbolt, and my team was Salamence, Tyranitar, and Starmie)