Thanks, that helped out a lot! Much faster than my first attempt using it. Wonder why I didn't see those equipping options earlier!
Was able to do this with that guide:

I am a newbie, first of all, and I have Strarf and Arnval uploaded. I was posing Arnval a bit in the Diorama studio and, unless I am missing something, I came to find that there is no easy way to equip them! Like her wings for instance, I had to upload them as an object then manipulate them directly...

I just started today. Bought my MMS figures at an anime convention last weekend =)

Owner name: Shujinkou

Noel (Angel type) Rank C
and
Tia (Devil type) Rank C