RE: Skis/Floats on the nexSTAR?
You can put skis/floats on about any .40 class trainer. Generaly the models have abundant excess power, and have no problem with the weight and drag WHILE THE ENGINE RUNS.
The added drag will be significant... and will change the trim of the aircraft. Plan on using 1/2 your up trim (assuming the mechanical, not digital trim, and the trim tab was centered with wheels) to compensate al level cruising speed.
It is suprising, but Skis seemed to add more drag than floats when I've put them on. the skis are smaller and ligher, but seem to require more trim correction.
DuBro makes Skis for .40 size models now. These are probably better designed than the ones I made 20 years ago. However everything I have read about snow flying still says that the longer floats give better results.
Don't expect to be able to taxi out and turn using floats on snow. Carry the plane out and point it into the wind. (have a helper hold it still till ready to take off, they slide in the snow quite well.)