Anuvin, sorry, all this talk of pinholes in foil led me to believe that the laser wasn't able to focus without it. You are right that there is a need to refocus with layer height. Although, it seems good for an inch or two. And moving faster over a given spot, but hitting it more often (so that it can still cure) has the effect of tightening the focus...but there are limits. This brings us back to the floating laser idea...