I'm not sure how you want to use it...

I dehydrate precooked meats for most trips, including hamburger and turkeyburger. I suggest that you use the leanest stuff you can find, cook and season it, then pat it down (some people rinse with hot water) to get rid of as much fat as is possible, then dry it at a high heat (145F). If you dehydrate the stuff just before your trip and use it early into the trip, then the fat content is less of an issue. Even so, I have never had to throw any out...

I only use stuff like hamburger for adding to chili, or stew, or similar dishes. I don't expect to get "fryable" hamburger back by rehydration.

I start rehydration around lunch time (when I remember) by placing the stuff into plastic jars and adding just enough water to completely cover the meat. Later, several times during the day, I add a little more water and shake the jar to keep the stuff wet. By just adding only the water necessary each time you can end up with an end product that is very much like what you started out with (and not have water with meat floating in it).

Good luck!

-aj