Hi there,
So the number of workflows, unless you are close to the cap is not really the issue.
My suggestion and I run some things off of long workflows with logic and branches and others where there is one for each action is to use the triggers and the goal as part of the deciding factor.
If you run one workflow per event, and the event is a webinar and the workflow is there to get people who attended a webinar to sign up for a free trial, goal: form submission to sign up for the trial. Then you can use if then logic based on which webinar they attended and have multiple webinars in each branch - as you dont want a person to get three different nurturing workflows with the same goal - you may just want them to get it the first time they sign up for a webinar - and not the next time. etc.
Thats a short explanation but if you do start another thread let me know and we can engage further.