No worries, but usually when you challenge a guild to a premade, you should at least have a whole 10man group ready (meaning that you know exactly who will be playing, which roles, what kind of strategy, who plays what role etc), or at least have 10 people who are sure they will play in your team, so that you can start practising right after you've challenged a guild.
INB4 petty comments about HSA's history with premade challenges etc ^-^
