Exploring Ebberon - Variant Capstones.

Purchased Exploring Ebberon, was interested in using the Variant Capstones and other Artificer upgrades.

I have Partnered Content for Visionary Productions ticked and own Forge of The Artificer. 

But I do not see an option to switch capstones at higher levels - why not. 

Do I have to Hombrew the entire class just to test out the variety option from the book I just bought?

You're always best checking the release thread for new books. From the Exploring Eberron release thread:

NEW CAPSTONE FEATUES

The book features 7 new capstone features.

We cannot support alternative capstone features at this time. 

Well that sucks.  Will they ever get around to it, I wonder?

Maybe they'll support modifying class features with the eventual rebuild they talked about.