I agree with Luke, go down with the arrow but if you really want to use the noggin, I use htX4, some people use htX3+20 at high alt and htX3+15 below FL250. FM is more conservative, greater than htX4. The FM doesn't seem to like doing DECEL during decent. It normally plans DECEL quite far out at an intermediate STAR level off point.
Have fun.
MAS