I think a good latch is one where they are getting milk efficiently and not hurting you, so for that reason we tend to encourage young babies to take a good mouthful of boob when they latch. Once that's well established, you don't need to worry as much. My son sometimes does the "lazy toddler latch" where he's not really hungry, but wants to nurse for fun, so latches badly on purpose to slow the flow. When he's actually hungry, he goes back to "eating like a baby" and his latch becomes more traditional.
As for positioning, I find it pretty hilarious that there are actual "methods" for how to hold them while eating. I have fed my baby sitting in chairs and rocking chairs, couches, cars, and the floor, using cradle and cross cradle and football hold, with and without a nursing pillow. I have fed him side lying down on the bed or couch, semi-reclining with him on top of me, and dangling my breast in his mouth while crouching over him as he lies down on his back. I've fed him as he straddled my lap. I've held him while he nursed in one arm while walking around cooking or even brushing my teeth, I've fed him squatting on the floor with him balanced in my lap or while he's actually standing up, reaching for my breast as I lean forward in a chair. I've fed him while he was in the carrier, I've leaned over to feed him while he was in the car seat or when he was on the changing table, being changed by my husband.
Feed the baby sitting in whatever way you damn well feel like. The idea that there's one way to "position" a baby to nurse--even a newborn--is utter nonsense.