The problem with using the A shape as the X axis for the roof's generator is that the tiles on one side of the roof will be upside down. Ideally you would have a separate generator for each side so that the tiles are correctly oriented. There are a couple of ways to do this.
Firstly you could use a closed spline for each pitch of the roof and use it as a clipping path. There's a script to make this a little easier you can download from here
and see used in the video below.
Alternatively, In the attached file I've adapted your roof so that it uses only the ridge spline and a pitch and size parameter to set the angle and length of the roof. I've also added the ridge tiles to this too and tried to make them adjust automatically to the pitch. Here's a little video of it working.
I hope that helps, please let me know if you have any further questions.