Yeah, wooden roll off seem less dew laden. I was an occasional user of one thats 10 years old and only now showing need of TLC. I only once encountered water on the scope optics when opening up.
As it happens, I ordered an additional dewheater which arrived yesterday. I will try mounting that down by the mirror cell of my Newtonian and leave it on when not observing. I shall see what happens.
I will also start assembling the RPi bits for a longer term project.