Does anyone know how exactly Mermaid Creations' pay $600 dollars down, the rest later plan work?

I may have the down payment soon and have been hired for my first mermaid gig this summer, so could pay after the end of the summer. Is this too uncertain to make him comfortable?

I have a silicone/neoprene tail for the mer-gig, but I think it will draw so much more attention if I can have the silicone tail before the end of the summer.

What do you think? Could we work something out?

I sent this message to Jesse too, but I'd like advice in case he says no.