thank you Dipscom and cellli. we've been using edge animate and google web developer, both of which have polite load built into their publish settings, but would rather use gsap for better compatibility and control.
just to be sure (sorry if i'm annoying), some typical banner specs might be "initial polite load: 64kb. total load: 2Mb." so if I understand Dipscom's javascript, the page will only load my initial html containing that window.onload() and everything else (images, gsap/jquery, etc.) will load subsequently, thus satisfying those initial load requirements?