I played it today due to boredom. I've never completed it (still on Round 1 and have yet to beat the Poke Cup and Prime Cup) and have had it for about eight years now lol. That said, i've had Stadium 1 for longer and have only recently beat Round 1.
Either way, I decided to go through the Poke Ball stage of the Poke Cup with Ash's Johto team today - Pikachu, Bayleef, Cyndaquil, Totodile, Noctowl (not shiny) and Phanpy. All of them are rentals except for Pikachu from my Yellow version. At the moment, i've got to trainer battle 5, with Pikachu, Cyndaquil, Phanpy and Bayleef soloing one trainer each up to now. It's funny that I lost to the Beauty in the fifth battle, but I have so many continues that it doesn't matter xD.