No I haven't tried the .006" yet. First I'll drive a while with the .004 to get to know in that to see if there's a noticable difference between them.
Here's a link to the build thread for the sprinklers. Page 3 and scroll way down, like 3rd or 4th post from the bottom and there is an explanation for the oil sprinkler holes.
http://cal-look.no/lounge/index.php/topic,16934.60.html-Mikko-