Hi Mark,
You could create one standard webinar program - which includes the assets (e-mails, landing pages, forms) and the campaign steps. You can use this as a master program which you can clone over and over again.
When you create a form as an asset specifically to a campaign and embed it in a landing page, it will also be cloned, you don't need to change it.
So the only thing you need to do is adjust the e-mails and landing pages with the webinar info and you are ready to go.
Doing so will save you a lot of time, ensures everyone in your team uses the same set up of a 'webinar program' and gives you the option to tweek each webinar program to your needs (example, you could easily add or remove a form field for one webinar, without impacting other running webinar programs = which is the case if you use a 'global / universal' form).
Hope this answers your question.