 There are important differences between the relationship between ‘standard’ Newtonian particle mechanics and its best-matched alternative on the one hand, and the relationship between GTR and shape dynamics on the other. In the former case, the class of solutions of the best-matched theory is a proper subset of the solutions of Newtonian mechanics: for example, it includes only the sector of the solution space of Newtonian mechanics which ascribes zero angular momentum to the entire universe. Sometimes, this is marketed as an advantage of the latter theory: the best-matched theory predicts what was, in the Newtonian case, an unexplained coincidence. (For discussion, see Pooley &amp; Brown 2002.) In the latter case, by contrast, it has been discovered that one can ‘glue’ solutions of shape dynamics to construct new solutions, which are not associated with any particular solution of GTR (in the sense that they are not the best matched equivalents of any solution of GTR): see (Mercati 2018). Thus, the solution spaces of GTR and shape dynamics overlap, but the latter is not a proper subset of the former. Given this, it is no longer clear that shape dynamics can be presented as a ‘more predictive’ alternative to GTR.