Well to be honest with the way I trained my guys with all 12 manuscripts, 5 tombs ( 3 strudy shovel, 2 in map frags) then for codex (3 in pathfinder and 1 for the buffs). it works out great. Normal play time I search for buffs. Durring events for eggs or presents I search long searches.
This way durring easter roughly you can get 20 eggs a day using long or medium searches with gem explorers untrained . My trained explorers on Long search will get 42.6 eggs a day average or on medium 36.2 eggs a day. This is one of best training setups I found. i have 14 trained this way
Easter numbers this is my rough search numbers.