You know you would have to be standing in the middle of the monster to get the full effect of the 10 yalm diameter. Given that is pretty impractical on some mobs and the Rdm will be either in front or the back (or sometimes the side) a 5 yalm radius might be a bit too small since the radius is really what you are working with (though thinking about this I could see this backfiring horribly as a AoE refresh tool that forces the Rdms AWAY from the monster)