Hi Ralph,
For myself as a bass and guitar player who has to improv over chords and have used the "timed slashes", I think I would find the triangle heads the easiest to go with. There is no mistaking them for a "regular" open head note (half-note), and they don't have the "I wonder if that's supposed to be hammer-on or other percussive technique?" feel to them like the + or the x has in my mind.
YMMV
ttfn,
Sherry