This is a tried and true method for doing roof tiles / shingles. I recall buying a whole roll of HO-scale shingles back in the 70s, before I realized how dead simple they are to make.
One advantage to cutting them by hand is that the tiles / shingles will be less regular. Though you can easily change the regularity produced by your die by making a few cuts here and there. IMHO, a little irregularity makes the whole thing feel more real.

As far as the ridgeline is concerned, I decided to simulate planking along the ridgeline on this model. IRL you often see specially formed tiles on more recent roofs, or simply normal tiles laid lengthwise, because the concave shape of the red clay roof tiles so common here in some parts of France makes them ideal for covering the ridge. It all depends on what type of tiles / shingles you're trying to emulate.