My advice if you want to do a mace spec with prep would be:
1) If you use a non-dagger mainhand, ghostly strike is mandatory if you are at least 11 in sub. It is that good.
2) drop initiative to get ghostly strike and 2 points in imp sap, which means you only have to pull 1 point (prob from your assassination tree) to finish it.
3) I personally prefer the extra crit from malice over imp eviscerate. If you had cold blood and had to pick between the 2, i could see going evisc since you can assure it crits anyway, but without that I feel like just more crit chance for every ability you have is better.
Another thing to keep in mind is that hemorrhage is one of the only non-normalized attacks in vanilla, so the speed of your weapon plays a huge factor. If your wep isn't at least 2.6 or slower, you are going to be far better off with going sinister strike. Hemo really shines with the R14 weps if you ever get that far.