I don't think I'd overlap it. The raised edge will create a drag point when people walk across it, and it won't take very many shoe toes bumping that edge before it starts to lift. If you think aligning edge to edge is going to be too difficult, you might want to experiment laying it out as a mosaic in your design program and see what it looks like. Lay it out in a pattern leaving maybe 1/8" or 1/4" between the tiles. On a 24' oval, those gaps won't be that noticeable, and might even give it a more artistic appeal (depending on the design).
GetNoticed Signs & Graphics
With the speed of technology today, anybody who says "it can't be done" is usually interrupted by somebody who is already doing it.