I've been editing a couple of Mercury Living Presence releases, and they all have credits for recording director, musical supervisor, and technical supervisor. An example I'm currently working on (credits are on p. 1 of the booklet, cover art is uploaded):
We don't have (or at least, I don't see) any relationships for those roles. They might match the description of a producer (this indicates an artist who is responsible for the creative and practical day-to-day aspects involved with making a musical recording.), but I have no way to be sure, and besides there is a separate credit for a "produced". So I've been putting them in as "miscellaneous support", which feels rather silly as they certainly sound important. (And adding a sub-optimal credits annotation).
Just want to confirm I'm doing this right. Or at least as right as is currently possible.