First, you need:
1. Visual Boy Advance
2. A NA Pokemon Emerald ROM
3. Loads of patience
Simple, I will make a save file with Clefairy and Ditto in the daycare which will produce an Clefairy with Belly Drum, send it to you, and your job is to find an Adamant Magic Guard egg for me to RNG on.
Step 1: Run back and forth, back and forth, back and forth
Step 2: Wait until the old man has an egg
Step 3: Save (Save state or regular, works fine)
Step 4: Hatch/check the egg too see whether it's Adamant, if it isn't, load and throw the egg. If it is, load and send the file to me
Step 5: Wait for 1 hour.
Step 6: PROFIT!