BF weaning to formula

Hi ladies. My DD is 8 days old and we are EBF right now. I only BF'd my boys for the first six weeks and then we were using frmula. I only want to EBF her for maybe 2-3 weeks and then start gradually weaning starting with one feeding at a time. I have only ever gone cold turkey so this is new. Has anyone done this and how many did you drop at a time? I'm trying to avoid the engorgment and thought it may be better for her if I try to do it gradually. I started pumping two oz each day to introduce bottle and so far so good. Should I mix in formula when I begin? Any experiences? Thank you!