I've used a Red #25 and #23 filter to some effect on Mars, but I would describe the difference as subtle. It would not make a difference between seeing no detail on the planet and going "WOW!"
You may need a cooling fan for that big mirror. If the temperature is dropping more than about 1.5 degrees an hour, air cooling isn't going to keep up. I have found that when I am doing planetary observing, having the fan on makes a huge difference in what I can see.
I'm using a single-speed Synta Crayford on my f/4.7 and while I sometimes wish for a little finer control, it works adequately.