You can go old school and use a brush. With enough practice you might be able to match the splatter size https://youtu.be/iOzpbqqJeVE

Also, the water based texture sprays are junk. If you're going to use that, I'd recommend using the oil based type (stinky, but way better quality). Warm up the can in a bucket of warm water if you're not getting fine enough splatter. The good thing about oil based is that it dried in like 10 minutes, so you can sand it off and go again.