Stuck on last 2. 22d:"Great performer capturing music's foremost highpoint (4) ?c?? I think it must be acme but can't quite see how this fully fits the clue.
25a: "End of piece's spare with key material (5) ??o?y If 22d is indeed acme, then the first letter of 25a would be "e". It looks like it should be epoxy, which is a material, but how does this fit all the clue pl?