I started a TAS for this back when Tafatt started his and I believe a monk and 3 black mages is the way to go as well. I followed Tafatt's example when I started mine.
http://files.filefront.com/7181324
Goes up to me destroying the Canal. I made several mistakes though and like Tafatt, got frusturated at my inability to manipulate appropriate prizes out of the boat game and stopped there.
Thinking about it, you would want 5 emergancy exists total. Marsh cave (crown), earth cave (ruby), ice cave (floater), water cave (slab) and waterfall (cube).
You would also want to manipulate a bunch of Megalixers, one each for the unavoidable battles so you won't have to waste time traveling to an Inn, on top of several for Chaos.
Then there's also a few battles where you can make use of things like curtains and fangs.
For the record, I've got a party at level 16 infront of Chaos on my actual FF1DOS cart AND they're transformed. I can't even come close to killing Chaos with this group. (Knight, Ninja, Master, Red Wizard) Chaos kills my party within 4 turns.
If you're going for time, you probably won't transform and your party will likely only be level 15 instead.
So getting to Chaos at a minimum level is possible, it becomes a bigger problem to kill him unless there's some trick that he's vulnerable to.