"Excess power is required for floatplanes" is a myth and an old wifes tail.

The LT-40 makes a fine floatplane and you LA certainly will do the job. The key to a good floatplane is in fact the float installation not gobs of extra power.

Yes the floats step and it relationship to the final CG is very importand, On that airplane the step should be either at the CG or just behind the CG (not more than a quarter inch).

The airplanes wing must be at a positive angle of incidence to the floats top deck of around 2 to 4 degrees. In other words sitting on a table if the floats are blocked level the airplanes tail will be sitting a bit low.

I would not reccomend Gee Bee they tend to be problamatical if the installation is not perfect. There are many fine better performing floats out there perhaps the Great Plaines 40 size among others. Go to the seaplane forum and do a search on LT-40, float installation and LA-40,46's.

John