Bigger feathers catch more air and help spin the arrow and stabilize faster. Bigger does tend to be a bit louder, but I find after a few dozen shots they quit down. bigger will also fix minnor errors in form or gear. The trick is to find the legth that fits you and your gear. I know a few people shooting 5½" feathers, I've tried and found them too long. As for straight or hec fletch I have tested both to no real noticable difference in shot placement or arrow speed. Given, my arrows were matched to my setup, the hec fletch did spin noticably sooner. But shot placement was fairly constant between the two. I will say that hec fletching will spin your arrow sooner out of the bow, which does help if your not spined correct. In summation, bigger feathers with a hec (right, left), will help negate MINNOR flaws. But with propper setup you should have no issues with small feathers fletched straight.