Upsizing and a few more questions...

[Beach Mama]

Sizing:
Is it ok to upsize if bub is close to the next sized nappy?? James was nearly 5kgs at his 2mth check and is a boof man, the small magicalls is too small and Im looking at a HH but the med is 6.4kgs up I think James would be roughly 6.1kgs now.

Measuring rise:
When the sites give you the rise - is that something I can measure on him to check the size? and if so how do I do that?

As usual I'm sure I will have a bunch of other questions to come.

ETA: Ok here's another one. I use Aromababy barrier balm, can I use it on MCN?