Powerhead placement / aim

[Kryten]

So I've been trying to figure out how to place and aim my powerheads for the best flow without blowing sand all over the place. My current setup in my approx 30" x 12" x 15"tall tank is one ph running constant, and 2 others alternating off of a Natural Wave timer. Anyone have any tips for getting some decent 'wave' action and ensuring as few dead spots as possible?