Ah yeah with a C8 at f/10 the gain I mention should be in the ballpark at least, maybe a little bright. As you're using f/10 you can dial the capture size down (you need to quit and reopen EZP to achieve this) and bump your frame rate up by dialling down the exposure length. I'm using the colour version too with my C11.
As for the interface...it might be a little primitive, but I'm a Mac user so anything on Windows I find a bit clunky
but it gets the job done.
There are a couple of options you might want to set in the options. First is to use SER video format, it's the quickest/lowest load. Then adjust the USB transport down as low as you can without it stuttering. I use a value of 0 for this on a 4 year old netbook so no doubt most machines are more powerful than this and should handle it well. A lower value will maximise the frame rate the camera is allowed to send down the USB.
For focussing I use a bahtinov mask on a nearby bright star, I have no idea what the focus functions in EZP do.