There are a lot of ways of doing this... but the Oz Audio HR6 as well as the Furman system is an excellent way of doing this. For years, I've always ran the 8 busses of the master console out over balanced cable to the vocal booth, to a 8 channel "cheapie" mixer, which fed the headphones of the musician in the booth. Sitting on the floor was an old alesis midiverb so the musician could add some ambience to what they hear as I record everything dry as a bone.
Nowadays, with the Oz and Furman products, you really don't have to bother with all that crap and just use cat 5 cabling.
Though to be honest, I've never EVER had a client complain about a "mix" they heard on their headphones, no matter what instrument (or vocals) the musician performs, as long as it wasn't dry. Having used mostly 8-buss or larger mixers, I generally use busses 7/8 for stereo foldback to the live room or vocal booth, or whatever.