What is the earliest point to check the leader log for the next epoch using tools like cncli? I though it was 60 hours in to the current epoch, but keep getting the "Query returned no rows" error.
In order to calculate the leaderlogs, the calculations require the epoch nonce. This epoch nonce value is calculated from the rolling nonce value at 1.5 days before the next epoch starts. This 1.5 days is also called the stability window. The nonce calculation also includes the block hash of the first slot of the previous epoch.
Finally, if there is extra entropy that needs to be added, the extra entropy protocol parameter is included in the epoch nonce calculation.
By using these two (sometimes 3) pieces of data along with a blake2b hash, we end up with a new epoch nonce value that can be used to calculate leaderlogs.