If there will be a second League, then we need to forget about any other tournaments!"
Let's assume 4 months for one season. Then 120 days for 9 matches in the first league, 14 days per match; 120 days for 11 matches in the second league, 11 days per match. I think that's fine. Round-robin is the most objective format! In the Swiss-system, the draw decides, albeit not much, but still.