Both pekiti tirsia and sayoc are blade arts, sayoc is more specifically a knife art. My understanding of the differences are primarily on the training methods(sayoc kali is feeder based, whie PTK is going to cover offense and counter-offense equally). Sayoc system also seems to have less emphasis on the triangular footwork for flanking that PTK, instead having more intricate feints. In terms of how the actual delivery systems end up, you'll find that the sayoc praticioner should end up with smaller hand movments and less emphasis on power in strikes( the basic training tool benefits more from quick reversal than power), and will largely eschew defanging the snake, a very large staple of PTK blade training.
