Slow Roast Pork Butt

[Sundae]

I'm making roast pork tomorrow.
We call it shoulder but Merkin sites I've been to call it butt. Even though it's not :p

I have contradictory advice.
I want to make it Merkin style. In that I want to be able to pull it apart with a fork. British style roast pork is sliced - I don't want that. I want something totally different to anything they've eaten before and I want it melt-in-the-mouth. And yes, Americans do that best.

Now the general advice is to cook for 8 hours, allowing the fat to seep into the meat and the collagen to break down. Fine. But I've read that it's not possible to overcook it, you can leave it in as long as you want. And also that you can over-cook it and it will go tough and leathery. And one of the sites suggested that if you have a fan oven you need to turn the fan off. Well, we do have a fan oven, and I can't turn the fan off.

Also, some of the recipes I've read (I was going for a hybrid of my own making) say to cover it, but other forums suggest this traps condensation, so you end up steaming rather than roasting. I'm also torn between cooking in liquid (various ideas inc lemon juice, wine, water) and not. I think the liquid and the foil are not compatible.

I come to you for help.
Any advice?