Here is the dirndl skirt that I made the slips for. I got the waist band sewn back on and it fits just wonderful now. I used a tutorial from "Evange Sews" she makes awesome tutorial videos on youtube.
The only thing she doesn't say is how long to make the length wise part of the panel I just guessed and I can't rember how long I made it now, but later on I found a tutorial on "Gertie's Blog For Better Sewing" that explains it in a bit more detail.
It was very simple to make and won't have taken long except that I had to unpick the waist band twice. First because I sewed it down all wonky so the second time I used a boat load of pins and it turned out good but it was to big, so I unpicked it again and re-sized it. In the end it turned out pretty good even if it did take two tries at the waistband.