I would just cut the stops off the knuckles. You don't need to trim them both and the tubes are more of a weak point than the knuckles are.
Once you do that, you can also shave a little off the inner edge of the knuckle as you'll see where it now contacts the surface of the axle tube. Don't have a good picture of it, but someone else here might for you.
Once you do that, you can also shave a little off the inner edge of the knuckle as you'll see where it now contacts the surface of the axle tube. Don't have a good picture of it, but someone else here might for you.