Hi,
I'm not sure I fully understand what you are looking for. You need to have something that is used to trigger the job to be forecasted. If you don't use run days/run calendar, then you would need a condition like s(job1) to have it start. I'll assume you are using a condition.
In this case, the exclude calendar would prevent the job from running on those days and yes, you need to check off the use date/time conditions.
To see if it will do what you want, you can use the forecast command with the appropriate parms like jobname and date or from WCC you can use the forecast tab to create a forecast report to do the same. It runs the forecast command in the background to get the data to display.
Regards,
Mike