I run the desert also and there really isn't much more you can do than what you're doing now, you either trust the guy ahead of you and follow his line until you can over take or try to stay up wind and make the best of your own line. When I get swollowed up in the dust and the above options just aren't happening, I'll drop back and try to make it up in another area, sometimes I do,most times I don't, but also,I know there's 50 other guys fighting the same problem
One other thing is wear one of those paper partical masks, you won't inhale as much dust, which will help towards the end of the race and after.