Ask HN: How do you find the best business model using lean startup methodology?

We have completed to development of our MVP of our product and we are releasing our beta product. In searching for our most profitable business model, we are wondering how to continue using lean startup methodology if we constantly iterate the product and don't truly give each revenue-driving option time to resonate with all of our users. There are 4 revenue stream concepts that we are testing, however, we are unsure whether or not the amount of beta users are fair representations of what the true outcome would be if we went live.