The pic you posted earlier with two brackets I believe are just two of the same brackets, not a 292 and a 250 bracket, but this photo of yours may be a help to you.
Your new lower bracket I believe is the right one. You said this new bracket gets in the way of the old alt bracket, that's because the old bracket is not needed. Look on the bottom of the new bracket in the pic and you will see a curved slot where the top of the alt bolts into it. Removing the old alt bracket should let the new bracket sit down into place where the top three bolts line up.
Hope this helps!
