Congratulations! Are you sure you need a supplementer right now? Have you tried without it? Your body may surprise you. It can't hurt to try a feeding without supplementing, and if she becomes frustrated or seems dissatisfied after a reasonale time add the supplementer.
Like I said in response to your other post, I bought the LAct-Aid for my triplets, but never used it. They are 4 months old now, breastfed exclusively. I began nursing them the day they were born, and the birth mother terminated her rights as quicky as possible, so we brought them straioght home from the hospital. Prior to their birth I was only pruducing 2 oz per 20 min pumping session. Two days afer their birth, 8 oz in under 4 minutes. I can't tell you how nice it's been to just be able to use me and not have to deal with extra equipment, especially in public!
While I was in the hopsital with them the LC and nurses would observe my feeding, hear the vigorous sucking and swallowing, and saw that when the babies were hungry they'd cry, and after a good nurse they were satisfied. I would say you could make the same observations. especially if you have an LC to support. No one observed a need for me tu use a supplemetner in the hospital, though the LC said that with three babies I'd probably have to supplement at some point. It hasn't happened yet, and in two months or so we'll start solids. SHe said she was guessing, since I was the first adopting mom of triplets who tried to nurse in her experience! JUst see what your body is capable of.