onesies are wonderful. She will be VERY sleepy when she comes home and that collar thing would just make her uncomfortable. The oneies can be worn all day and night. When Layla was spayed she was 3 lbs and i bought premie onesies and they fit very well. I didn't cut a hole in them.. just stuck her tail through the snaps and undid it when she had to go out. Layla was VERY out of it when she came home and needed help standing when she had to pee. If your pup does't come home with pain meds (Layla didnt) be very careful when you lift her up. I'd buy or go to a pharmacy and ask for an eye dropper so you can give her water. Good luck. we are here if you have any questions