I can't see your pictures. Not sure if this will help but my first exposure unit (if you can call it that) was a 500 watt shop light on a PVC stand I made. The light was 18 inches from the screen laying on the ground with a piece of glass over the film. I put a 2 inch piece of foam inside the screen so the mesh and the film would be flatened out buy the glass. My exposure times were 13 to 15 minutes (I used Ulano emultion then). I did some really good halftones with that thing. I don't think I went over about 40 LPI.