No staffs work differently from spells. When the staffs effect expires the body won't turn to ash it just collapses allowing you to raise it again. Vampiric servant works the same way. That's why you have too use a staff with a fortify conjuration potion. The potion will boost the staffs effect making it last longer.

Letters from a friend will make the body permanent so it won't disappear if you leave the area. It's useful for certain quests when you can't bring the monster with you. Like the soul cairn.

I am new to the restore loop thing. About how many "loops" would you need to get the kind of amulet you are talking about? Also what levels on the skills for a minimum start on making it?

Good questions Demoquin I never bothered to count how many loops but I can tell you that I had a stockpile of about 20ish fish (longfin/spadetail) and enough salt to mix them with but I never had to use it all. For the fortify alchemy skill I just used the best I had or made some to the best of my ability I would try to aim for the 10-15% range I usually find at least one piece of gear at that level. You could also use Krosis. I suggest saving right before you attempt the loop just in case it doesn't work out as intended. That way you won't waste any fish.

Well that's a good start before I try and do it. Wouldn't yellow mountain flower be more beneficial for this?

Yes yellow mountain flower would be better. I can't remember if that cave is quest locked or not. If not then that would be easier to farm then the fish. I picked the fish for windstads hatchery. I can't remember if you can plant the yellow flowers either buy I don't think you can which makes the fish easier to stockpile.

I'm having trouble with the restoration loop. Any tips on it?