i switched over my pot from lead to lead-free. i emptied it out, took it apart and scraped it as clean as i could. did end up buying a new valve rod because it was heavily caked in lead that wasn't easily removed.
i buy bismuth and tin separately and mix them myself. anything between 75% to 85% bismuth will work just fine. the tin is added for strength, otherwise the bismuth is too brittle on its own.
buy the drop out spray. you need it 100%.
when curing the powder paint in the oven you need to reduce temp and extend duration. trial & error