How long in advance we need to claim a speaker

Now exactly one month in operation, we see demand picking up quite nicely. We had about 30 speaker requests, have placed four of them and most leads are still in process. In about ten cases we could not reach an agreement, for different reasons.
The speakers' fee is a reason for most of the clients to back off: getting paid for a speech might be quite common in the US and in Europe, here in China many organizations still think that labor is cheap, as are speakers. That is a mistake.
Because we just started we did get a few requests for a speech on very short notice. We were able to work very fast for a Danish business group, who will listen to one of our speakers next week. We do not mind to work fast, but are very much dependent on the availability of the speakers and some do have a busy agenda.
At lead time of one to two months would be not uncommon, even longer for international dispatches. Chinese nationals would, apart from dealing with their daily business here, have to apply for visas. Since they all have been travelling extensively abroad getting a visa would not be a problem, but still take time.
A few of our speakers are closely related to the central government and in some cases they would have to go through a domestic procedure to get permission for travel abroad. That procedure would take about two months and will only start after a deal has been closed.