When to divide miltoniopsis

[jcec1]

Funnily enough, yesterday I just divided one that sounds about the same size as yours. All the growths were on the one side, so I didn't like the fact that eventually one side would be old and tatty. I split it down the middle of the new growths and centred this area in the new pots. I like to keep my orchids smallish as I worry about the media not drying in the centre of the pot.