Thanks for the extra info.

Our self-extracting RAR (EXE) loads pretty quickly, even though it's
150+ MB. It's definitely not unpacking everything first. Once the
user choses the desired decompression location, that's when it takes
time churning through the files.

The larger file is primarily an issue for data transfer speed. Since
it's almost always "all or nothing", we could also pack the files as a
RAR, then install and execute that during installation, as controlled
by SB.

Mike Hanson