You really want some boning in the pattern - otherwise it will wrinkle really badly as you move around. You can always cover the outside of the corset in a fabric so that the boning channels do not show - that way you get the support and no wrinkles plus a "clean" look.
If you didn't use any waist compression I think a zipper would be a decent closure - easy to use and install. I've used velcro before and it's not really that great - I'd only use it in areas where there isn't a lot of movement - going along with that Zil said.
You could also modify the design slightly and turn this into a fake, shaped obi or something depending on what you'd like to do.
Disclaimer : This post written by a Grumpy Old Man
Actually in the pipes:
- Remaking Ser Loras doublet.
- Luke Skywalker, A New Hope
- Wind Waker starter costume in swim material
Eventually: Paul from Dune, Faramir, Harry Sullivan