Hi Bobby,
Glad to hear you're getting the hang of it. When you say you want to extend the roof on the ends do you mean you need to fill in those missing half tiles? If so I'd normally I'd set a tile roof style up like this.

- As you can see I've got two segments, one full sized tile and one half sized tile.
- The full size tile is wired to the Default input as this will cover nearly all of the roof
- To create the offset on alternating rows I've wired the full size tile and a half sized tile to a Sequence operator attached to the Left and Right inputs. The sequence operator is set to
Increment at Y to create an offset pattern vertically.

- To prevent tiles being sliced on the sides the generator's default mode is set to
Adaptive. This subtly rescales the tiles so that they fit exactly.

- And that's about it, of course if you want to add subtle variations you can do this by using the segment's Random Transform parameters.
If however you meant you'd like to extend the whole array slightly over the ends of the roof then that's a different issue. It that case you'd have to adjust the clipping splines to increase the size of the array. You can't really do it any other way because anything that extends beyond the spline will be clipped and if you turn off slice for the segments they won't be cut correctly on the top or bottom of the roof.
I hope that helps, please let me know if you have any further questions.
Many thanks and have a good weekend!
Paul.