Because of the short length of the blazers, the helical will not end up being that much on a blazer. I don't think you will have a problem. What I would recommend is getting a few blazer vanes and giving them a try. Your shop might be willing to sell you just a few to expirament with, or there are some places that will sell them individually such as eaglearchery.com
If they don't want to sell you a few, ask them to fletch just 2 or 3 for you, so that you can give them a try.