Diapers for big newborns

[Lammy]

My daughter ( our 1st child) was 9lbs 5 oz 21.5 inches long at birth and wasn't cloth diapered until about 18 months old and we just bought a bunch of BG OS. My son (our 2nd child) was 10 lbs 9 oz and 21.5 inches at birth and immediately fit into his sisters BG OS diapers- the only thing was the rise was right at his belly button- and it made me a little nervous with his umbilical chord. I am wanting to go and get some smaller sized diapers for when our 3rd child gets here ( this is our last baby) and I was wanting to know if it was worth it to get a few newborn sized diapers with the umbillical cut out or if small diapers would work because I have pretty good sized little ones. I'm looking for recommendations on sizes, brands, types ( we use everything from flats to fitteds to aio's). Any help would be greatly appreciated.Thanks!