My bad: I used one msg for three questions So, let me break them out now.
Of course you are right, mod_deflate is the correct choice.
I can just "order it" from ServePath Support, but I would like to cut my teeth on your advice and learn to do it myself...you imply that it is a supported module in VirtualMin. Where exactly does one to go turn it on? I don't see it as a checkable item under "Features and Plug-ins" and looking thru all WebMin panels (I wont' say i didn't miss it) I don't find any place to enable apache modules.
then, of course, I will I need to add
to httpd.conf for a server-wide implementation. which I presume I need to do "by hand" like I did on the old server.
"mod_deflate, on the other hand is a standard module, and easier to use (and more compatible, since it's been a standard a lot longer).
Basically, you'd just need to load the module, and enable it either site-wide or on a per-directory basis. If you want to make it a part of only some sub-directory on your system, you could add it to your Server Template(s) in the Apache website section.
Here's the docs for mod_deflate (which I'd probably recommend over mod_gzip, due to its existence in the standard Apache codebase...it'll probably be more secure and more reliable):