…The long-standing duo of percussionist George Barton and pianist Siwan Rhys, hereafter GBSR and augmented here by flautist Taylor MacLennan, offers Morton Feldman’s homage to his erstwhile artistic comrade Guston, along with Why Patterns? (1978) and Crippled Symmetry (1983) in a wonderfully annotated six-disc set commensurate with the label’s other Feldman and Cage boxes, for which all involved have been justly lauded. The label has made a specialty of these two composers who are, clumsily and too often, still associated with the New York School, a designation that does the individuality of their work no justice. It is, however, music for which performance traditions are still in formation, making these sets doubly important for the deep dives…