This would be the best option. Expecting people to sit around and hit refresh for more than 15 minutes is not reasonable. If a conditional system can not be integrated, it would be best just to postpone to the next day.
Thanks for update. With this conversion looks like all gold/silver ingots should be converted to coins and then all coins sold. Who wants coal from gold or silver? Sounds like alchemy gone all wrong! Any better date guess for implementation of these changes?