Can you spray paint if you have just a poster paint tub of that color ?

I want to make an evangelion EVA-01 cosplay. I managed to find a tub of the purple that was close enough to the primary color of the mech. I planned to first apply multiple layers of sealing glue (to get it looking more shinier) and then brushing the color on it but that leaves visible strokes on the foam. Sadly this colour is not available as a spray paint. I'd REALLY prefer if I was able to get a more smoother and uniform finish.

Would love any and all ideas for how to go about it. Thanks !