Heads compatible with IronTech upgraded skeleton from 2017?

[SiliconeDevil]

Hey guys,

One of my dolls is an IronTech "upgraded skeleton" from 2017. I'm trying to figure out what my options are for changing out her look with a head swap. Glancing around, it looks like the newer stuff IronTech is currently selling is either using a threaded post, or a new slip on style that works in place of the threaded post. Unfortunately, that doesn't match up with my girl's connector.

Anyone know where I should be looking for head options? So far the closest thing I've come across appears to be the DollHouse168 heads. I'd just really like to know for sure if something is going to work before I buy.

Any help is greatly appreciated!