Check on line insolation tables for that location at that time of year to see how much sunlight to expect daily.
Need to know if panels will be flat on roof or if you can tilt them up facing South where you are parked. Or will they be ground mounted (portable) so you can aim them South tilted up? Can you move them around during the day to aim at the sun plus have them tilted up?
Big difference in AH haul per wattage of panel depending on your set up.
Most have flat on roof so it doesn't matter which way you park, and no fuss with portables, but it means more panel watts to get the job done.
But if the roof has too many obstructions so you can't get many panels in the open spots, you have a limitation there. You might have to use several small panels instead of a few big ones.