The tail mold is to make only a tail section ...
So...you might mold up a bunch of red tails....then place one into the mold..and then inject black. And you are correct you don't need the tail mold...unless you like to make two color baits.... a lot!
You could mold up a red Stump Thumper...cut off the tail (wherever you want)....put it back into the mold and then inject the top.More time consuming...but cheaper. Just keep remelting the leftovers!
Basically, you can un-mold after about a minute.....but be careful of hot plastic in the sprue (the point where you inject). ALWAYS wear gloves!!!! The good ones that Jason sells are great!
Note: After a few worms...your mold will be really hot...so it will be longer between "cool downs" and being able to un-mold the worm. Just be careful!
Keep asking questions....this is a great place to ask any question and everyone from beginner to expert are happy to help!