How to change default preview mesh for a skeleton

WixZ is right.
And actually you can do it on multiple Anim Sequences at once by shift-selecting them in a Asset Browser tab → right-click → Set Current Preview Mesh (will apply whatever SK is currently previewed in Persona).

Note, this right-click option isn’t available for Montages, which is a riddle to me.
I’ve created a new post about it there:

https://udn.unrealengine.com/s/question/0D5QP00000389TL0AY/rightclick-set-current-preview-mesh-option-does-not-exist-for-montages

Sorry for taking 5 years for responding, LOL