Well until you can drive like Surikarn, I'd give countersinking the top deck a shot... Just use a regular countersink bit, and only go until the screw is flush. If you go too deep, you might not be able to tighten it all the way, because you'd be trying to tighten the bottom of the flathead screw into the posts. If you dont go deep enough, it looks like ass
Also, before you run, make sure all of your screws are tight on basically anything that could tweak. I know on my Surikarn at least, there's a lot of aluminum to thread into, without loctite, the screws do have a chance of vibrating loose.