Pushing generally comes in one-stop increments at the labs -- besides, a 1/2-stop push is a bit wimpy. You're better off modifying the grain increase by exposure, i.e. push one-stop but only underexpose by 2/3, 1/3, or by none to compensate.
You'd be surprised at how well a 4-perf 35mm anamorphic image handles a one-stop push as long as you are consistent with your exposures. Besides, your project takes place at night and anamorphic lenses are not that fast, so I'm sure it would be helpful to have an effective 640 or 800 ISO, for example. You'll mainly see a mild increase in contrast which you might need to compensate for in lighting.
Look at what Dante Spinotti did on "Red Dragon", a two-stop push on 35mm anamorphic but he didn't rate the 500T stock at 2000 ISO, he rated it at something like 1280 ISO so he had some extra density on the negative.
The main thing is to be consistent and accurate with your exposures, hence why a lower rating than what the push tells you to use gives you a safety margin.
It's a short film, so be bold!
And when in doubt, shoot a test.