Re: brinsea octagon eco 20 temp range
I can not tell you about the incubator you are asking about. I bought a Humidaire long before Brinsea were available. I do know that you can purchase an Inkbird controller that has a pretty tight differential and a remote probe to control your incubator if it proves to not go low enough for your use. Look for them at a home brew supplier. I have one running right now for seed starting bottom heat.
Working to propagate my survivors and staying treatment free USDA Zone 7b