you will never get the arrow to stabelize with strait fletch with a low profile vane you will need to put as much helix in the fletch as you can and still will not get very good arrow flight with a 4 blade muzzy but will work fine if you want tp continue using mechanicals

I would recommend using a bhoning blazer vane on a off set or helical for fixed Broad heads. The Flex Fletch is just not tall enough to catch enough wind to stabelize Fixed heads but the bohnings will work Great!