RE: LT-40 on Floats-No go!
From the pics it looks like the back of the floats are still in the water. At takeoff speed, only the step should be in the water. All LT-40's I've flown needed a little down elevator trim to fly level. Try a little down elevator which would lift the rear of the floats up and hopefully speed the plane up. If this works, add a little down trim. Also, the water is smoothe which makes it more difficult to break loose. A little more chop would help. I'm not familiar with the LA's but I've heard they are not powerhouses. Hope some of this helps.....Seaplane