Thanks, Gosailingnow, a nice compendium of advice from someone who has been there and lived to tell us what worked, and by contrast, what failed to kill him...
The advice to run off in a fin keeler/modern flat-bottomed boat is sound, I think, and makes your advice to use every scrap of information available to you an important point. We have a steel full keeler and can heave to, because we are planning on short-handed cruising with a kid and I can see situations in which we will have to get rest. At the same time, we are thinking about devices like the Jordan Series drogue for running off in a controlled manner (keeping moving under hull speed) because we have very strong deck bollards. On my fin keeler, I have torn up genoa track in 25-30 knots during overly enthusiastic tacks, so I can't see lying to a sea anchor/parachute type of device using deck cleats...the shearing forces would be enormous. I have heard of sailors tying them to the mast and thence through a fairlead, however.
I encourage people to attempt to heave-to (nobody lies a-hull these days, it seems) in their boats of choice. Some can, some can't, but you want to know if it can in really stinking, throw the boat around weather, which means, I suppose, going out beyond a shielding piece of land (or picking the right wind) and trying to slow the boat to a 1 knot crab, while at the same time having the ability to run "under cover" if things start breaking or you learn that in fact you can't heave to. I am of the opinion that all heavy weather tactics, just like MOB exercises, should be practised under controlled conditions close to home, but in worse weather that you would usually seek out. Just getting used to doing the "Frankenstein's monster walk" to and from the mast while teathered means one less unpleasant novelty when you have to do it for real.
Lots of good advice there, anyway. Thanks.