It is always best to be prepared for anything that might happen. There are people who are okay to do it without preparing, but I do not advise it. I want people to come prepared for everything that they are doing. Sure, it takes an awful lot of time to do that, but believe me, it is all the more worth it. You can save yourself a lot of anxiety by preparing things ahead of time, I really do feel like it.
Instead of asking players to trade, affected players simply tap individual groups of gems.
A place to share my inspiration, sketches, ideas and works in progress! Hope you enjoy!