As always, coaching by an experienced method expert on the first project is recommended. Evo is results oriented, so not much is sacred in its adoption other than frequent evolutionary delivery and project management.
Clear, precise, and measurable (though evolutionary) requirements are not that common or enthusiastically developed. One approach to motivate their adoption is to focus early on evolutionary delivery, which of course demands understanding the design ideas, requirements, alternatives, and priorities. Thus, after a few iterations, the participants themselves will better appreciate the value in adopting something like Planguage and greater requirements precision, in order to guide choosing their next step and evaluating the results of the prior one.
Gilb recommends the use of pilot projects to demonstrate the value and viability of Evo.