Feeding in separate enclosures can reduce the association with something entering the enclosure for a feeding opportunity. However, some animals are pretty placid and don't get aggressive per say or make that association, esp when your hands don't smell like food items.

I feed all of my snakes in their enclosure (including my green trees) and have never been tagged by any of them later mistaking my hand for food. Once fed I do not handle them or anything for at least a day so they have time to "turn off" their feeding response. So far so good.

As for the feeding regiment, the breeder knows your animal well and I would stick to the feeding schedule he/she had that animal in ( obviously accommodate for when the animal is in shed). But you should always pay attention to your animal's body condition and response to feeding and make sure you are feeding at a rate and size that is comfortable for the animal and does not leave them under or over fed at all. You will figure this out with time as you get to know your snake.

Some of my animals will feed no problem after a stressful event (like shipping or transportation) and some do need a week or two to settle in to their new environment before feeling secure enough to eat. I would definitely wait one week before offering food. If your snake doesn't take that food item, then wait another week before offering food again.

Hope all of that helps!