My initial weight and balance (solo + 0) is on the forward side of being perfectly balanced. I am allowed 108 a 116 and solo the figure is 109.5. While this is acceptable, for my first flight I want to be as balanced as possible. I added a #100 lb of silica sand to the cargo bay. I reran the numbers and the data said that my center shifted to 112 which is in the center. I ran it twice...once with 40 gallons of fuel for my takeoff and again for 25 gallons for my landing figuring I burn about 15 gallons durning my short flight. The calculation stayed pretty much in the center. I had the local shoe repair place make four nylon loops that I fastened through the carpet into nut plates that were installed with doublers when I put in the floor. I used regular straps to criss-cross the sand bag to secure it.