Turkey's a bit of a tricky double whammy for dryness because it tends to not be as fatty as a chicken, and being much bigger it requires cooking for considerably longer. Hence it needs probably more fat added to the bird than perhaps most people are used to (esp. if you treat it like a chicken) - when doing turkey we'd generally slather the bird in butter and then lay about 12 rashers of streaky over it. It's also important to have a fat-heavy stuffing (e.g. more sausagemeat than usual).
When cooking it we'd cook it for half an hour at gas mark 8 to cook the outside and get the fat melted as quickly as possible, and then put the bird in a tinfoil hat at gas 5 for the rest of the cooking time, and thus you end up with a nice succulent turkey.
For what it's worth, most of our stuffing usually gets done outside of the birds as well, but only because stuffing is hugely popular in our household (to the extent that we'll have cold stuffing sarnies in the following days) so we always make twice as much as normal.
I've never had a "wild" turkey, but a family member keeps chickens and I've had the immense pleasure of eating a genuinely free-range chicken from their back garden. Vastly different in taste and texture (gamier and much more "meaty" in the mouth) from the sort of chicken you'd buy in a shop and stonkingly delicious.
I come from a small family so we've never had more than a meal for 6 but I think I'd need two ovens to deal with 8 or more people.