Any here tried to find a castle+berry garden secret island?

The latest mod has 4 secret per island(include the radioactive zone) and one is chainsaw. And in principle you can meet a castle+berry garden combination . I think if this happen it will be a ultimate place to set up a camp and make a full item collection, castle is great to store items and beautiful ,indestructible ,while berry garden in principle is a pernament base and you can live here without scavaging. But the chance to meet this is <1% , even by some way to save load and speed up the search to less than 5 min/island , I did it about for 200 islands and still get none. Anyone here tried to do so? Is there a faster way to do so?