A deposition apparatus (20) comprising: a chamber (22); a process gas source (62) coupled to the chamber; a vacuum pump (52) coupled to the chamber; at least two electron guns (26); one or more power supplies (30) coupled to the electron guns; a plurality of crucibles (32,33,34) positioned or positionable in an operative position within a field of view of at least one said electron gun; and a part holder (170) having at least one operative position for holding parts spaced above the crucibles by a standoff height H. The standoff height H is adjustable in a range including at least 22 inches.