the Question is if this skill suits your entire set. and i say it does. i cant imagine that such a strong Ninja would lose his fights easily or even lose at all to an average opponent and missing a +3 HP wont change this fact much. but with FoF it could give him a big advantage for the long term in case he´ll get MA and face many opponents with shock, sabotage , sai or whip which he can not deal with.
but as always: Exploring paths for perfection is the most important thing in muxxu , so you will have to try both in 2 ranks so pick one and try the other one next rank :)