I would recommend reading the walleye section of this forum as well as the tip-up section, more info than you could use in a lifetime.
In Nelson, I would recommend finding contours in the 10-18' range and setting tipups in a line hitting all of the depths inbetween. Set your 5 tipups and then jig with a minnow.
Yes, there are perch in Nelson. I fished sunday 7 am- noon and caught 15 NICE big perch. One of them was truely a hog, pushed over 12" and was FAT, just a hog. Even compared to the 10-11" perch on the ice he dwarfed them. Also caught 4-5 walleye and missed a decent northern. Nothing huge, but good action.
I'll be at the derby as well.