Good suggestions .....
In addition to having a firm understanding about the coin, get the cat a set list so he has an idea what you guys are doing. And be sure to talk to your band mates about the sub ... too many times the band is assuming that the sub will play exactly like you do, when in fact that's rarely the situation.
You should also be up front with the sub if there are some band issues, for example, the drummer rushes his fills, the guitarist doesn't always tune up properly, the set list can change at the drop of a hat, etc .... It'll make the evening easier for all that are involved, and it will make any future sub requirements easier for your band mates to swallow ....
