Webtrends Optimize has two differing approaches to test delivery and traffic splits. You can serve multiple projects, which can overlap, and so share the 100%.
You can also have multiple experiences within a single project, which split traffic between them.
This example shows how multiple projects are served in parallel, each test within a project can have its own % share (even or custom), and each variation within a test can have its own % share (even or custom). If the test receives an effective 10% of traffic as per Test 3, the variations at an even split get an effective 5% of traffic.