I had a few options in front of me, that I know of, and was wondering if anyone had more suggestions. I wanted to keep it 1.3 based
Scala is what you want to use. Its easy of use is impressive, and it does exactly what you need. In contrast to other options, you will probably still find example scripts and tutorials using your search engine of choice.
I think the last version that runs on 1.3 is ScalaMM 200, but the Scala distribution contains a separate player for your presentations ("ScalaMMPlayer" or something like that) - maybe the player from later Scala versions still runs on 1.3?
If that's the case, you could use whatever Amigas you have at home to generate your presentation and then just use the A500 and a floppy disk to play it.