Basics questions about dew protection for SCT

I'm finally approaching being able to buy the Celestron 8SE I've been eyeing for a couple months, but have a few questions still hanging about the accessories needed, like dew protection. Currently I have a 70mm achromatic refractor and a 150mm collapsible tabletop dob and neither have had any noticeable issues, but I understand the corrector plate of SCTs are much more prone to fogging up from dew. I also live in a Scandinavian coastal town, so while it's seldom hot, there's a fair amount of humidity, even in winter.

*Dew shield and heater* - what are the pros and cons of using a dew shield with integrated heater vs a simple shield with a separate heat band?

*Dew heater controller* - first of all, are they necessary or can you usually just run a heater directly from the power source? Also, I find controllers with 1, 2 or 4 channels controlling 2 or 4 outputs; how many different things usually get a heater? Is several heaters more for photography than visual, or is it useful for basic visual as well?