Feeders by general rule should be no bigger than the thickest part of the snake.
At some point also feeding every week will most likely turn into them going off for several weeks/months. My girls ate every week for around 14 months, after that it was a game until I went to every 14 day. Now one of then feeds every other week and the other once a month. They both go off for a few months each year during Spring/Summer. Usually 2 months to 5 months. Once the Albino went off for 8 months and that was the first fast after eating every week, she was around 18 months old.
Sent from my iPhone using Tapatalk