why do my lugnuts loosen themselves??

[CSGAS]

You are also increasing your "scrub radius" and offset when you move your wheels 7/8" away from the line your spindles turn on. This extra effort not only create more wear on your tires--leading to your heat--but also overworks your steering. I would guess you have power steering? The fluid is probably getting hot like your wheels are...it won't likely be burnt but it won't smell fresh on your finger either and will look orange instead of cherry.

This is where a front or 4wd offset wheel will actually "solve" your problem, except for the obvious desire to use the wheels you have as evidenced by all the trouble you went through to use those centercaps!

I had a very similar situation with a 54 Plymouth and a custom disk brake setup adapted to the stock spindles, but only ended up with a 1/4" spacer after some trial and error...and error and error.