FX Wildcat 3 22 cal slug options?

Nielsen Slugs work amazing in my 500mm Wildcat Tube version. I have been using the 17.5g in several rifles, and they are awesome. Great accuracy and lots of punch for bigger pests. The 20.2 grain are also supposed to be exceptional but I have a big pile of the lighter ones to go through first. I have a regular STX Superior liner too and they are easy to get good speeds out of even with a mostly stock rifle. No problem pushing them 950-1050fps, especially in a Wildcat BT.