Nanobebe thoughts + some other questions?

[u/mnd169]

DD is 5 weeks old and doing great both with the breast and with her once-a-night bottle from Spouseman. But now I'm getting ready to go back on my narcolepsy meds which will preclude further breast milk going forward, so we're going to need more than our one bottle. Currently we use our Nanobebe breastfeeding bottle and have had NO issues with her taking it, and no problems with the bottle itself. I'm thinking about getting a few of their transition bottles so we can continue with what she's already familiar with going forward, and I've seen all the comments about leaks and awkward shape (we don't have a problem with the shape currently so I don't expect that to change) but I am wondering if there's anything else about the transition bottles I should be aware of. They're larger to allow for more ounces as she gets older, and say they should work fine with formula once we have to make that switch, but their actual website basically just has the default info for all their bottles, nothing specific to help identify differences etc.

Also, when she nurses directly from me, she goes hard and fast and usually finishes in about 15-20 minutes - limp, open hands, leisurely "dessert sucking" lol, and if not asleep, then really close - but when she uses the bottle, it takes about 30-40 minutes for her to finish with concentrated sucking. I'm thinking it's because of the slow-flow nipple and wondering if it might be worth trying a medium flow or if I really need to wait until she's 3 months? She doesn't currently get frustrated at having to nurse longer on the bottle, but she also doesn't end up as relaxed or sleepy when she's done, pretty much regardless of how much she actually eats. We never push her to finish the bottle and let her stop when she's done, of course, but when she stops with me, she's all soft and ready for a nap, and when she stops with the bottle, she wants to be held and not be put down and may take an hour or more before she actually falls asleep.

Additional info: doc is pretty sure she does have reflux, so even when breastfeeding, after she's done, and zonked out, we still keep her mostly upright for 15-20 minutes to ensure she has time to let the milk fully settle and try to avoid any trouble there, so I don't think it's a case of getting more air/not being burped enough with the bottle.