a preliminary question that should be addressed is that of the best strategy to take advantage of such a wealth of data. In this paper, we primarily focus on the AMS-02 B/C data [@AguilarEtAl2016a] and investigate how much they can constrain CR transport, aiming at defining new benchmark models.

An ambitious approach would be to proceed with global fits of all available data, attempting an overall and simultaneous understanding of CR sources (all species) and propagation. However, this approach is prone to mixing uncertainties of different nature, with the risk of devaluing the actual strength of the data by introducing poorly controlled parameters (for an illustration, see [@CosteEtAl2012]). Since our current understanding of CR measurements has more firm elements in the propagation part than in the source one, factorizing out propagation effects from source effects, while inspecting their physical plausibility a posteriori, seems justified. In this article, we proceed through partial tests of key aspects of the current propagation paradigm, with the goal of validating it or highlighting its breakdown. An important and relatively new issue in this area is that systematic errors are often dominant over statistical ones. This requires a change of perspective in well-established practices of analyzing 