Noob building a SaaS platform

Wondering if anyone has some advice as to options/routes:
I have been developing a prototype website (Drupal 7) application. It's not very complicated, but tailored at a specific business niche.
Originally, I was going to offer as an additional website to some of my existing clients - I think I just assumed I would use the prototype as a template and create a new standalone website each time I needed too....
But now that I have the application workflow process nearly nutted out - it occurs to me that this might be a candidate to release as some form of Software as a Service - Just pay me a subscription, and I'll give access to your users to a set of data on the platform.
I'm working through this idea.
I think the two options that I have at the moment:
1. is going down the full blown Aegir based "site spawning" path, where new subscriber gets a new instance generated. This looks to be the route that is most future proof - however I would have to hire in skills to make all that work I expect. My Server-fu is not strong. I only understand 50% of the references I read to these set ups.
2. Using Organic Groups as the basis of the data segmentation, and just having one big site that I manage with multiple groups. I have seen some references to people doing this with OG and Ubercart (to manage the subscriptions). Hopefully I can find a path using OG and Commerce.

It should be noted that I expect I would probably only have a dozen or so clients on this service (realistically), each with maybe 10-20 users each. So not big end of town by any means.

I'm tilting towards the OG option at the moment, simply because I think I might be able to work that out (eventually) myself (with google's help). I may even handle the subscription/payments manually.

Does anyone else have thoughts/alternatives?
Anyone running small scale SaaS platforms willing to share (at a high level) the conceptual site(s) architecture?

Cheers
Jason