Assuming you want to find a great balance between virality and "ninja mode", you've got your prelaunch landing page set up and want to get your first hundred subscribers while avoiding virality, which you'd like to get one week prior to your launch or so (you want to talk first to those first subscribers, do some A/B testing etc.).
Phase 1 [Ninja Mode]: I assume at this phase you'd avoid using anything that may create virality (which would go into Phase 2). But how would you get the limited number of subscribers / customers you want? Will those be very targeted personas / friends?
Phase 2 [Virality / Big launch]: You fully unleash your marketing campaign: giveaways, referrals, PR, emailing, content marketing, social media etc.
Basically, how would you find balance between those two phases and how would you set up the transition, whether gradually or promptly and how?
Examples I think of: Harrys, Dollar Shave Club.