The reason why it's uneven is because you are impatient with the paint. Spray one line across, stop, then back, always in the same direction, do not cover it all in one coat, just a light "dust" then do it again, and again, and again, then get a piece of wet 300 grit sandpaper, sand it, then dry it and get all the dust off, then paint it a few more times, over and over, till it looks right. (flat black is hard to get spray lines out of, but it will go away) Once all is smooth, spray down a crystal clear clear coat a few times and finish it off with a piece of #000 steel wool to get rid of any tiny bumps, and viola! It is beautiful.
But if you don't want to do all that, just spray it with gloss black or a glossy dark grey, the spray lines will be un-noticable.
Also your unfinished dash will be impossible to clean in that state. It will always look "dusty." You can also try "plastidip" next time you want to see something in a particular black before you get to the paint stage, you spray a couple even coats, and it will give you a black rubber coating on the piece, and with a lot of pressure, the coating can be peeled off with no damage to the piece you "painted." Plastidip can also be a permanent solution. You can use it on wheels, dashboards, speaker grills, etc... etc... you will become addicted and plastidip everything you own pretty much.
