Thanks for that.
1. He actually has a couple of iMacs. Not being able to find any controls, I ran Eye-One Match on Easy mode. At the end, one Mac had Gamma 2.2./7300K/132Lum. The other was 2.8/6800/92.
Presumably, there's not much I can do to bring them closer together?
2. If I can persuade him to buy another Mac for imaging only, which of them is fully adjustable?