Use the attachment to determine the heat + humidity combination.
You ask about optimal heat and humidity. According to
Dr. Bugbee, optimal heat range is 78.8F - 84F, and the RH range is 40%-70% with 60% being optimal. But if any of the other growing parameters are out of whack, then it doesn't matter. For example, if your root zone is too cold then it will stunt your plant. And optimal humidity changes depending on which growing phase the plant is in. Again, checkout the attachment.
Good luck!