This is a complex question with so many variables but, the quick answer is you need to find out what film works best on your specific machine and create a chart so you can go back and reference it.
Here’s a best practice to follow for temperature settings.
1. Run hot enough to make sure the adhesive on the film is “wetting out" or has a tacky feel. Then run slow to start so the adhesive looks wet and shiny, if you run too fast it will have a cloudy look.
2. Next test sheets to make sure the bond is good. Take the laminated sheet and cut a shallow X with a razor knife, try to cut only into the film and not the stock, then try to peel off the film. On offset or ink jet prints you should be pulling up paper fibers, on digital print especially dark coverage you won’t be pulling up fibers but should be pulling up toner and it should take some effort to pull up.
3. Write these settings on a sheet before it goes through the laminator, that way if you get a good result you will have record of it. Record your good results into a spread sheet so you have quick reference guide.