I've run a few experiments here and I think the easiest solution in this case is going to be to create a few new RailClone styles to create the hip tiles and valleys.
At the moment I can't find a satisfactory solution that adds these elements automatically, so I'd recommend you use linear arrays to create a line of hip tiles as per the example shown in your image (alternatively you could model a custom hip tile, but each hip with a different angle would need its own tile). This can however reuse the existing splines that are already used to define each roof area. To ensure the hips only apply to the correct part of the spline, set material IDs on the path and use the Generator's Limit By Material ID
In the attached file you'll find an example style called rc_ridge_and_hip
. It has many exported controls so you can adjust the angle between the two roof faces, tile overlap, rotation material ID and more.
To create the Valleys is a little more of a challenge. I've worked on the assumption that you need to cut the tiles back either side of the valley and add a kind of gutter (in the UK they are often lead lined). To do this you could adjust the shape of the existing splines to create a gap, but I've tried something a little different that used the VRayDistanceTex material to create a render-time boolean.
To do this create a RailClone object that stretches a simple box along the spline, turning on Weld Vertices to ensure it is a solid object. Any geometry that falls inside this box will be removed from the render. In the example scene this is called rc_valley_cutter
. Next instance a V-RayDistanceTex map to the opacity slot of all the tile materials.
Turn on Inside Separate and set the distance to 0cm. Add all the RailClone objects that are being used to cut out the valleys to the DistanceTexture's Objects list.
If you render now, any geometry that is inside the RailClone objects is invisible.
You can then use the same spline to add the valley details. This should be a simple L1S array, again limited to particular parts of the roof using material IDs. in the attached example scene there is an example called rc_valley
I hope that helps, please let me know if there's anything else I can do. I'm keen to explore the use for RailClone for roofs so any feedback is valuable.