I used the Jacobs Baits Pro Series Injection Press for the first time last evening and today. I am very happy with it. This is the link, in case you are not familiar;
http://stores.jacobsbaits.com/injection-press-pro-series/
I only fired up one side, but ran three (3) different colors through and it was flawless. I made 4 cups of plastic per batch in the microwave and added it to the pre-heated reservoir. I set the temp at 300 and it was rock steady.
When the reservoir was empty the air pressure blew the nozzle clean and I made the next color. All colors were clear or white and I had no discoloration from start to finish.
This is an expensive system, but clearly the best I have used or found. Making 50 to 100 baits in a batch is perfect for me and once the plastic is in the reservoir there is no smoke.