A Hystrix or a Retic would last in an enclosure that size for a good number of years.
I can't say an exact number because each ray is different when it comes to growth rate. This is due to a number of different factors.
The Retic can reach up to 18 inches in width and over 30 inches in length. The Hystrix can reach up to 14 inches in diameter. You will eventually want to upgrade