Hey, I don't think I ever responded to your message on my wall from a few years ago but no, I didn't RNG Gen 3 on Desmume - I did so using the Visual Boy Advance emulator under the tutelage of a nice guy named Bond here on Smogon.
Hi King, Im new rngig on 3 rd gen, but now i learn how to do on Ruby an Sapphire, I triying learn how to abuse of my SID on Emerald emulator, but I don't understand what i need do to generate a compatible Sid. I use some scripts to rng on R/S. Since that on Ruby and Sapphire is more easy because they are generate at the same time. if you can give me a guide or steps to do, im very grateful.