Using a larger bucket is analogous to getting more traffic in at the top of the funnel. You can achieve this in many ways, for instance, through media buys, user participation, and so on.
What’s very important is that you make it possible to track conversion end-to-end from a certain source all the way to sales related to that source. Like that you can make informed decisions about which traffic works well for you, and which traffic does not.
Again, AB testing can help you with landing page optimization to increase conversion on those sources. A single landing page per source or campaign will help a lot in splitting out the traffic, and can make it a lot easier to customize the environment the user sees when they first reach the site to match their expectations.
If you find that traffic from a certain source converts below average, ax that source, and replace it with a better one.