If your Portfolio has a history of delivering several systems in the past using similar architecture and platforms, the best way to do high-level solutioning estimation is using empirical data. When we say empirical data, we are saying to compare the proposed system or new release to a similar system or release that was delivered in the past. Once you have a baseline reference, you can then convert the person days to normalized points. From forecasting the normalized points, then the number of Lean | Agile and shared teams can also be predicted based on the requested delivery date.