If you can only take on a certain number of events in one day and want to keep track of availabilities, you’re in the right place!
First, create a Service called “Wait List” (or something similar), select “Track conflicts on this service,” and then add in the max number of projects you would want to to do in a day.
Next, add this Service from Fulfillment to each of your Projects; this way, the client won't see it/won't be charged for it. (NOTE: It is not common to need to do this for every project, but rather is typically used on popular dates such as holiday weekends).
This will allow you to see all the Projects that may be overlapping with this Service in one day. Once you reach your limit for a day, take a look at the other overlapping Projects that still haven't signed by clicking on the conflict alert icon.
Finally, disable online signatures for those Projects by clicking on the Project’s “Settings.” You can re-enable those signatures should one of the other confirmed Projects cancel.
You can use this tactic to track 'Blackout Dates' or to know when you're approaching your limit of projects per day.