How do you connect your two 250w solar panels in a 24v system?

The best would be parallel as these panels normally have > 30V output voltage, which would be sufficient for a 24V inverter/load.
There is also a risk of overvoltage on your charge controller connecting them in series, check if your charge contrroller can accommodate the sum of the max output voltage of the 2 panels before attemptins series on this configuration.

There are additional efficiency advantages of connecting your panels parallel.