Okay, here's some sample backgrounds for Lone Ranger:

1, 2, and 3 each have progressively more descreening, which makes them each a little softer, but it depends on if you just want a nice smoothing of the print screen but it's still visible (like #1), or have it almost completely removed like #3...


The 4th image is the current background from the MAME artwork file, and then the 3 images all in one (huge) image so you can see them all together, in a
0 1
2 3

All of these match the size of the one in the artwork file (so that 4th image is 4x the size...), so if you like one you can just grab it for the artwork file. I can use the same settings on the others to make them all look similar.