As to the welding, you will have to satisfy yourself as to the welding. Make sure they are on there, still pivot and that your don't warp the axle housing in the process.
You need to build a plate that will put the wheels centered in the opening, like the article says sort or like a lowering block. As hard as this is to visualize, this will essentially take up the 2 inches as the perches pivot.
While its apart, you could weld up the flanges and redrill if you have to have six lug. Hubcaps will hide it anyway.
