I am using ultra light spinning harnesses with great sucess not only do the gills hit them the smallmouths like them also. I use a slight jigging action and the fish seem to hit them on the fall. I fish with a 4.5 foot rod with a Abu garcia cardinal with 2 pound test in clean water and 4 pound test in water with brush or rock bottoms. The 2 pound test does not forgive at all on a snag.
Depends on the size!
Walleye size might not good for ultra light!
Homemade spinner hasrnesses like size 0 or 1 and no. 8 hook might be good for ultra light ..... 6 lbs line would be better for just in case to land a nice catfish or bass. Use minnow for crappie or white bass. Nice rig for openwater slow trolling for panfish! I do use 4 lbs line but I use at least 7 ft rod for reduce break line from bigger fish!
Check bait rigs in google.com and there's a small company (I think) in Wisconsin make spinner rigs for panfish!