Interesting, frank and unsurprising view from Cron, saying how alarming it was to actually enter true IMC with no previous experience. And that was when he knew he was at 4000ft with lots of clear sky just below - and an instructor right alongside! Now add the stress being totally on your own, with a very cloud base that makes the exit options tricky, and you can probably double the level of angst!
Going IMC to prove the point in an R22/44? Am not an instructor, but don't like that, (a) because it's illegal and more importantly (b), because there's got be to pretty high risk in that accidents will result. So is the instructor instrument rated? Recent experience? Machine's suitability? Hmm. We know from the Hislop accident that it doesn't take much disorientation in an R22/44 to end up cutting tails off. Sure many instructors can do this well. But can all, all of the time?
So as Crab says, use an IFR machine and IR instructor. But then jumping out of a 22/44 into say an IFR 355 for an hour is likely to be so alien and overwhelming that the purpose may well be swamped by the totality of the new experience.
Back to the 5 hours instrument awareness to get a PPL. I'm right with those who think it's a bad thing, tempting those who can be over-confident. But the initial requirement is only part of it - what "instrument awareness" is subsequently taught/tested? Does the annual LPC include it? And even after getting your full IR, you'd be pretty poor after 3 months of no instrument flying, let alone a year after 5 hours instrument awareness as a low time PPL.
So as far as I'm concerned we're right back to either being VFR or IFR, with nothing in between. Frankly it is not difficult to keep out of IMC, if you are motivated to do so.