It will depend largely on what kind of string you are using. Linen/B50 has more strands, while fast flight has fewer, and it varies among makers. Check out Silent But Deadly Bowstring online. It’s a very thin, well-made and exellent string and I think even at that high draw weight their chart will recommend 8-strank. Others here will (I hope) wade in with more opinions and suggestions. You definitely want FF for a Widow.