I use two small screw drivers against each other to spread the clip open, I usually don't have to fiddle with it too long.
I like to make sure everything is nice and free, a lot of the time I file the plate so it doesn't stick anywhere. It will be obvious when you get it apart. If the stock distributor has a light and a heavy spring, quite often the factory light one with one Mr Gasket really light one works well depending out the rest of the combo.

Sheldon