TC - I think you'll find that the CFII in brackets in Nigel's post refers to the FAA qualification - Certified Flying Instructor (Instrument), and suggests that he chose to go into IMC with a CFII during his training......
On the other hand, a few decades ago I qualified as an FAA CFII (fixed wing) without ever having flown in cloud - all done under the hood, which was then (and maybe now) perfectly legal.
I never did use the qualification as I shortly after went over to flying helicopters
(sorry, not doing very well today, guess you are referring to the bit about choosing to do it with his son.......)