Hey Don, what PVA do you use? If you use Aleene's Tacky, let me know how it flows through that tip. Also, if you happen to have a caliper/micrometer, can you let us know the diameter of the tip? I recognize how they built it - that's the tip to a metal mechanical pencil, and I tried to build my own the other day by scavenging a pencil tip and attaching it to the top of an Aleene's Tacky bottle, but it was only a 0.5mm pencil tip and I had to apply too much pressure to the bottle to get it to come out - I couldn't apply it in a controlled manner. It would probably work OK with a thinner glue like Elmer's but I prefer the lower-water-content of Aleene's.
I can also highly recommend spraying the model with Krylon Preserve It! (Matte or Gloss) before building. It makes a huge difference in how easily excess glue cleans off, and more importantly it prevents the ink from running under such glue spots. Every single time I build a kit without spraying the pages first (like my recent FG F-4 Phantom), I get a spot somewhere on it from excess glue or a water droplet or something. Never gotten one on my sealed pages. I have a thread on spray sealing in the Tips and Tricks section, check it out for a further discussion.