If you are going to use Acrobat, why Acrobat 4 and not Acrobat 5?
Because 4, as a component of eCS 1.2 and as a slightly different stand-alone version, is all I've got. And 3, with a forgotten level of WPS integration.
One of the different files of v4 is MSVCRT.DLL. I'd prefer 2 identical installs. The OS one may be the default, but install scripts can use the identical clone which is always there, regardless of the OS in use. The OS one requires REGEDIT2 settings, so you cannot just copy files to create a stand-alone version.
I have to start Lucide twice to open a PDF file, so that's not a working alternative for a new default PDF reader yet.