You can also make a solid tube with tail by making a drop plug put in after the tube is filled . If you are blessed with engenuity put splines in your plug and they will make a nearly pre - cut tail .
I have done similar to Roger but find dipping still quicker and overall better results. Now for small tubes you can just fill the test tube let the plastic set and then slice. I have done this for a long time on some baits with fair results. I wouldn't go any bigger than what I have pictured, but most don't have easy access to smaller test tubes.
you are making the easy, difficult. pour the plastic in, wait a few seconds, pour the plastic out. let cool,pull tube out of test tube, cut tails. my test tubes are mounted in plaster