Pingman,
I have not installed turnouts after laying track, but I have installed Gargraves uncouplers. Cutting Gargraves track is fairly easy when it is down, a razor saw or Dremmel tool goes thur the tinplate without much drama. It does present the same challenge as any other track in making the cuts to length, square and true. After the cut is made, it is easy to fair the ends by hand with a file. I have not worked with the stainless steel Gragraves, only the tinplate.