I think I may opt for a new secondary holder/spider from Protostar, and purchase the optional built-in heater. Very clean design: I put a Protostar secondary holder in my 10" a couple of years ago. It's the 2-legged curved holder and I think it's really great. Some people love diffraction spikes. I hate 'em, and they're gone. The adjustment is really easy too. The whole block is a stiff rubbery composite. I had my doubts at first, but it takes adjustment easily and holds it.
I'm sure our average humidity out here is much less than that of New England. Ever see a swamp cooler in Boston? Never even heard of one till I got here. Average humidity in the summer is such that your scope chases the dew point all night long. Some nights, big drops of water would roll down the collector plate. In the winter (one of the best times for observing in New England, except for the frostbite), everything would frost up. There are lots of things to miss about New England, but humidity isn't one of them.