Re-emphasizing what MM was getting at regarding delamination and splitting when trimming a carbon fiber prop: don't use a scrollsaw, jigsaw, bandsaw or the like. I suppose if I had to shorten the blades a lot, I would go get the finest tooth blade and cut chordwise, not thickness-wise.
CyA on the finished tip helps guard against future delamination and splitting.
For a molded, glass-filled prop like a standard APC (gray) practically any method works, so chop away to your heart's content.
Dave