If you dry at I think it's over 140, the meat is cooked, I don't like how it tastes then. And around 125 or so it dries. Some say key nutrients are lost when cooking it, I don't know, all I know is that the meat tastes way better dried than cooked.
Depending on the cuts, I do it in a few ways:
for fatty, great tasting stuff, like skirt steak, I soak it in brine for a while to get it a bit salted, that's to inhibit bacterial growth and help preserve it. Salting meat, you may recall, was one of a few ways we preserved meat in the old days. Then I dry it until it's as dry as it's going to get with fat in it. If I'm not going to use it soon, I stick it in freezer bags, and when I take it out, pre trip, I dry it a bit more to get any moisture off it. I don't use that much salt, nor do I soak it that long, just long enough to get the salt in the outer layers. But since the strips are thin, that's a decent amount of the meat.
For lean meat, I dry it until it cracks. There's no timers involved, it's done when it's done. One advantage of using lower temps is that it doesn't over cook, it just gets a bit drier as it gets done. I use lean meat to make pemmican, ie, a 50% by weight combo of dried then ground to powder/filaments lean meat, and low temp (below 240 F) rendered beef fat.
Thin slices in all cases are best, as mentioned. Ideally grass fed beef, not coming through industrial slaughterhouses, which I think is where a lot of serious bacteria issues are created. Might be wiser to use higher temps on any corporate style meat, coming from chains. That's all industrial meat, very dirty.
I prefer drying ingredients to meals, that way I can just toss stuff into the pot and rehydrate it. This also, I find, is a great indicator of what I actually like to eat on the trail, since what I come back with, or ate last, pretty much shows me what I liked least each time.
Hint: for spices, drying ginger and grinding it up is incredibly good, as is drying habeneros and serranos. You have never had anything like home made ginger powder, the flavor difference is stunning.
Also remember the other options, cured meats like jamon serrano, lomo, prosciutto will make you think you've died and gone to heaven every single food stop you make, and that food was developed to stay good without refrigeration.
For vegetables, using lower temperatures results in a far better taste and quality experience as well from what I am finding, it's the cooking vs drying thing again. You won't get that totally crackling dryness at 125, it's a softer kind. Except for things like rice and potatoes.
I stopped buying commercial dried meals after realizing that trip after trip, my emergency last meal for extra day out never got eaten, that was the store bought freeze dried 'food'. Now the food that never gets eaten is a dried bean thing I bring just in case I want one more day, heh.