For my third pour, I tried a different approach. Previously, I was pouring urethane into the open mold, then closing the top onto it once it was full. This time, I'm starting with the mold closed, on an incline, and used a turkey baister to squirt urethane into the mold. I started at the bottom of the incline, so the urethane had to work its way upward into the mold.
The turkey baister was one of the 99 cent ones from the grocery store. nothing fancy. I actually didn't even use the squeeze ball. I had to open up one of the vents a little bit with an exacto blade so I could get the tip in there a little better. I filled up the baister with urethane, and let gravity do the rest. After a while, I ended up blowing into the thing to push more urethane into the mold, which worked out really good.
A few hours from now, and we shall see how it turned out.