So, the bottom line is that the simple kWh/day/m2 * panel efficiency * m2 of panels should be within the theoretical ballpark of generation, but the real world

So, the bottom line is that the simple kWh/day/m2 * panel efficiency * m2 of panels should be within the theoretical ballpark of generation, but the real world is a harsh mistress and will undercut you. On that calculator resource, they provide a monthly and hourly spreadsheet, but even with the more detailed numbers, I was still failing to corroborate their presumably much more sophisticated modelling which accounts for other losses. Thanks. Just spit balling numbers and trying to see what things look like.