Hi Mark,
I would have to say that i prefer 1 - a couple/few turns on the reel. My most commonly used leader length would be around 3.5/4 metres, this gives me some turns on the reel and a drop of around 1.5 metres which i believe is a must for the proper casting technique. I would have to physically measure it one day but i believe a relatively long drop from the rod tip is essential.
With all that said, i do use short leaders too but not as often. I prefer to be casting with the mono shock leader rather than the braid which feels uncomfortable.
You can also use shorter leaders that make the connection postion much further up in the guides or even just outside the tip. Often these are used in conjunction with a slim profile connection such as Midknot etc and when used outside the tip help to eliminate wind knots - i.e. the braid travelling faster than the shock leader, or the braid forming loops within loops. I guess it is all personal preference and what the conditions and underwater terrain dictate on the day.