Bra fitting advice please

[Pastamancer]

I have just bought this bra in a 38GG and 36H as I'm not sure what size I need. I have measured myself and am happy that a 36 band is needed but measuring suggests a 36J and the cups are gaping when I try that size so it appears I need smaller cups than my measurements suggest.

I need to return them as they don't fit but am hoping for some help on here to suggest what to try next. I want underwired nursing bras and there aren't many out there so narrowing down what size to try as much as possible would be very helpful.

Problems:
Central gore does not sit flat
Cups gape
The sides gape at the top above where the wire ends

Thanks

Did you scoop? as that makes a lot of difference to getting all the boob in the cup

You put your right hand under your left armpit and scoop all the flesh into the front then do the same on the other side

quite often boobage migrates round the corner and unless you show it the way it stays there, it should all be up front

How does the band feel if you put the bra on backwards? Snug but not too restrictive? You should be be able to pull it away from your body further than a cm or so.

Yep I scooped and the 36 band fits fine.

Over the style doesn't suit your shape. Can you go for a face to face fitting somewhere?