"I dont want to copy a new acad.lsp file to their cpu casue it may change some user settings"
I agree that the mnl would be a logical place to do what you want. However, I'm curious about the acad.lsp reference. Several points...
To load in every drawing, you'd normally use acaddoc.lsp, not acad.lsp. And in most setups I've seen, both of these are deemed company-standard files, not user-customizable. This can be a pretty complex issue, which files the user is allowed to personalize. It's a balance between maintaining company standards, simplifying routine file maintenance, and allowing a reasonable degree of latitude for personal preference without compromising the standards.
I've never used a startup lisp to change any "settings," and have an aversion to anything about a file being altered upon its being opened. I want a file to open exactly as it was saved. Don't want any of my profile settings changed either, I want everything that's kept in the registry to remain the same as when I set it last.