Free Trial Period & 'Mark Paid' Questions

I'm launching a new site that uses LM PayPal Paid Adverts, and to get the site well-populated for launch I plan to offer an initial, free 90-day listing period for the first 300 ads to be published. After the first 300, ads will cost $10/mo and each listing will begin with a free, 30-day trial period. I know how to set up the 30-day trial and monthly fee for the regular listings, but I can't figure out the best approach for the first 300 ads that are supposed to get 90 days for free.

I considered having the admin simply mark all those ads 'paid' manually, but I don't see how the user is supposed to renew the ad once this is done since the PayPal Publication tab no longer shows an option to pay. Since the users who created those 300 ads won't have been asked to provide any payment information or go through any PayPal transaction, it doesn't seem like auto-renewal should be possible. I see that I have the option to mark the node 'unpaid' too, but I assume that the moment I do this the ad will stop being visible and will stay invisible until the user logs back in to pay for it. So here are my questions:

1) When the admin marks a node as paid, does it remain in a 'paid' status---not subject to any renewal period or renewal warning emails---until the admin marks it 'unpaid'?

2) When the admin marks a node 'paid', then marks it 'unpaid' later on, does the node revert to the same 'unpublished' status as a node that was never paid/published in the first place (i.e., is invisible, has PayPal Publication tab option to pay/publish showing)?

3) When the admin marks a node 'paid', then marks it 'unpaid' later on, when the user pays for/publishes the node is it treated like a brand-new ad that's eligible for Trial Period #1?

4) I assume that anything I enter for Free Trial #1 will automatically be applied to new paid ads, but what about Free Trial #2? Does it automatically follow and extend Free Trial #1, or can I configure it to be used for a specific content type or user role---i.e., use Free Trial #1 for all new ads, but use Free Trial #2 to offer a different trial offer to specific users, roles or groups? Or can I make Free Trial #2 conditional---i.e., if an ad has been repeatedly renewed for some minimum period of time, user gets a free listing period tacked on at the end of the paid period?

Thanks in advance for your guidance, and for the great module set!