The triangular ones sound like NACA ducts, you'll see these on aircraft & racing cars. The actual hole is oblong and at the rear of the duct. The square holes on the kit are probably vents of some sort for the engine or tanks. Can't help with a G model, but I do have a quick build review in my files of an F model, from a Brit magazine. The main points on the kit seem to be; the decals are a little thick but settle with micro set/sol. The drop tanks will need filling along the join. Add lots of weight to the nose to avoid tail sitting. The mag by the way, was Scale Aviation Modeller International, April 2000. good Luck