Completely independently I came up with a similar system.
I also used 5" lengths of 1" PVC. I put round caps on one end drilled for a bolt or something similar. To limit the lube fillout in the endcaps I used a large washer in one. In the other I filled the endcap with hot glue. For my mold stand I used a Forstner bit to drill a hole the diameter of the cap in a length of 2x4. Centered in hole that I drilled a smaller hole for the head of the nut that runs the length of the tube.
For plugs I used a hole saw to cut plugs out of pine and (while spinning the plugs in the drill press) used a rasp to taper them. I cut the bottom off an old funnel to fill the tubes.
Everything went fine, with only some spillage from over filling one of the tubes. No pictures right now because they're out in the garage and its 25* outside.
Then I wondered how to get the lube out of the PVC and though to look on the site. You guys were way ahead of me.
One dowel and a washer later I have my first batch of lube sticks. The next batch in in the garage setting up.
Thanks.
David