I agree, there's no such thing as a completely perfect night -- here least of all -- but I'm a visual deep sky observer and last night (as well as 99.9% of previous nights) was simply not up to observing DSOs, faint or otherwise. By the time the cirrus moved on (9:30 PM), it was too late. It's an hour to a dark site and I wasn't even packed.
Dew in the Gulf coast states is a problem year-round, actually worse during the fall / winter. I don't have a SCT but I use a Dew-Buster on my Dob and refractors. The Dew-Buster is very good at efficiently doling out power only as needed, plus the designer (Ron Keating) is very responsive and helpful to work with. I have heater strips on the (refractor) objective, eyepiece / diagonal, finder eyepiece, finder objective and red dot finder. On my Dob I have a Kendrick secondary heater, but I had an AstroSystems DewGuard in the past and it's a bit better. The Kendrick certainly works, but the DewGuard has a sensitivity adjustment, etc. I have a fan behind the primary on my Dob but the way it's mounted it causes minor vibration visible at high power (I need to fix that). I use it only to cool the mirror before observing - I've never had any primary dew up while observing.
I also use all the passive dew measures I can, such as dew shields, shroud, etc., from the get-go. Plus, I don't leave eyepieces out unless I'm looking through them. In cooler weather I keep them in a soft pocket so they'll stay warmer (not a factor right now, LOL).