You can ask the GAL if he will be submitting his report to the court, assuming that's what he was ordered to do, before he is paid the full amount he billed. The GAL doesn't represent you (your lawyer does) and thus would not be going to court on your behalf. If the GAL has not been paid by the time of the court date, and the court's order anticipates or requires payment by that date, I expect him to raise the issue in court.

Generally speaking, courts don't adjourn cases "without a good reason."