No choice, I had to shoot the M405 / various vanes with FOCs. The FOCs were indexed 6/12. The 300s were appx 1" lower than the Blazers/SK200s which had the same impact points.
Multiple groups were shot with each of the 3 vanes: SK200, SK300, Blazers. Every time the groups were virtually identical, w/i 0.2" with each vane configuration.
Here are the results: all at 80 yds off a Hart adj rest/#13 rear bag, no flags---
SK 200 - 1 1/4"
Blazers - 1"
SK300 - 1/2" time after time
I've NEVER obtained this level of accuracy ever before. Group after group. I just kept shooting the 300s 3 shots after 3 shots (only have 3 practice FOC broadheads.

This is the 3rd group. Others were all the same.