Pro Site free trial or coupon?

I am setting up a new multisite installation and will be using Pro Sites to charge users to activate their sites. Once the site goes live I won't be offering any free trials. But I want to do a special offer for a select group of early testers. I want to give them the first year free and then charge them after that.

What is the best way to do this?

1. Turn on the free trial and set it to 365 days? I assume this will still set up the subscription in Paypal, but not make the first charge until the anniversary date? What happens when I want the site to go live? Can I just disable this and then new members will be charged immediately?

2. No free trial and use a coupon code? Can I do a coupon for 100% discount for the first period? Will Paypal accept this (I know it rejects $0.00 transactions normally). Then I just disable the coupon code once all my testers are setup?

Or is there a better way?

Thank you