Benton B, I do understand where you're coming from, but.... I think that by asking he could be pointed in the right direction, thus not having quite as much trial and error as you suggested. Just my opinion.
Now to give some ideas;
loco, theres a post up right now that talks about attaching curly tails to lures, I think this might be done in the same way. I have never made one of these so this is just from what I have gained in information from this site.
I would try getting some SS (stainless steel) wire and epoxying it into the lure, The applying super glue to both the tail and the the wire and inserting the wire into the tail.
Another option is to make a cork-screw type thing with the SS and epoxying it into the lure then just twisting on the tail.
You can learn a lot from this site by using the search tool. Try searching for tails, curly tails, plastic tails, etc.
As for making the plastic tail, I have no experience at pouring plastic, but there are a few tutorials about making your own plastic molds. I will include one of those those below.
Here are a couple links to get you started,
Attaching Curly Tails-
http://www.tackleunderground.com/forum/showthread.php?t=7755&highlight=curly+tail
Making A Mold-
http://www.tackleunderground.com/forum/showthread.php?t=10677