What speed should I set my 8mm camera to in order to use Ektachrome 100d?

Hi. I have a Bell & Howell Director Series Zoomatic 414P Regular/Standard/Double 8mm movie camera. I don't want to over expose my roll of Ektachrome 100d and was wondering what setting I should set the camera at? I know that in order to shoot in the daylight the camera's haze filter needs to be on. The speed settings are: 40, 25, 16, and 10. Thank you for your help.