I have had several 4 Stars of every size and I have found out that if you slowly add tail weight, about an once of lead at a time, the plane will be a better flier especially on knife edge. It your balance is right the plane will fly hands off inverted if you fly level without a sink rate. You will also have to cut down your elevator as the plane gets closer to being tail heavy. If you fly a lot of knife edge and advanced flying this will make a big difference. If you fly intermediate level flying don't bother with changing the balance like I mentioned.