Alien,
I have used 8x16x5 on the wheel side of the RPM knuckles, with just a little dremeling and then pressing the bearing in place. This was to use the LST2 CV. The inside knuckle bearing, 15x24x5 worked but it is a little sloppy, thin spacer (pop can thickness) is needed along with a spacer (7/8"od x 5/8" ID x 3/16" thick) to keep the inside bearing from moving toward the wheel. To make it all a snug fit I used a bearing race 8 ID x 4 wide to space between the hex and the outer bearing. See attached picture.

Kirk