You must have replied as I was writing the above post. It's an ARF, so it's almost together when you get it. You have to mount your servos, run your control linkages, set up and mount the fuel tank (the formers up front are cut out for the tank, you just stick it in, basically). I used a fueling attachment from DuBro and used a 2-line setup for mine, it made it easier than having to take the fuel line off the carb to fuel and defuel, which is difficult on the Rascal, because the engine is fairly enclosed. All you see is the cylinder head under the cowl, which doesn't detach. The wings fit together with an aluminum joiner that sets the dihedral (less than the Avistar). You have to mount the aileron servos (dual servos, one for each aileron, out in the wing), and it has some nice covers that conceal them.

If you have basic building skills and basic tools, it should be straightforward. The instructions are clear and complete; it would be a great transition to building a kit- there's very little gluing, and no covering to do. You do have to glue the horizontal and vertical tail and align them properly.If you have some help from your friends, it should be easy.

As far as inverted engines go, I've only run 4-strokes that way so have no personal experience with inverted 2-strokes. The glow plug on a 2 stroke sits right on top of the head, so upside down it acts as a little reservoir for fuel to collect in and it tends to be a bit harder to start. An idle bar glow plug helps, it tends to deflect fuel droplets from the glow element at low engine speeds. Using an electric starter will probably eliminate most starting problems, the idle bar will help idle, everything else will take care of itself. I only have one 2-stroke, in my Superstar (LA-40), and will only have 4-strokes because I love the way they sound and run. Both my glow engines are inverted mounts, my L-4 (Cub) has a .65 Saito.

If you use the 2-stroke on the Rascal, I'd recommend a remote glow starter attachment, because the glow plug will be a bear to get to and still keep your fingers. The plug on the 4-stroke angles back; it's still kind of inconvenient, but at least it's away from the prop. If you were to get a 4-stroke, the .56 is a great engine for the Rascal. The .65 case is too wide to fit between the engine mount (I tried). The .72 case is the same width as the .56, so it would fit, but approaches overkill as far as power goes (I've often thought it would be awesome, though, and not too much for a floatplane, given the extra weight and drag). I use a 12-5 Master Airscrew prop and it is a good combination with the .56. A 12-6 would also work. I tried a 13-5, but it's almost too much prop for the engine, it doesn't rev as well. With your GMS, I think an 11-6 or 11-7 would be okay, you could try a 12-4, but might not get as much speed.