SOLVED
After several deletions, reinstalls, and restarts, here's what seems to work:
- Make sure ArtStudio Pro is linked to iCloud Drive.
- Upload brushes to iCloud Drive
- Choose "Import ABR/TPL/Artstudio." This will load the File Sharing pop up. Navigate to iCloud Drive and download each brush from the cloud.
- You're not done yet. You have to do it again. Choose "Import ABR/TPL/Artstudio" for each brush you want to import. Navigate back to the iCloud Drive and import the actual files you have downloaded from the cloud.
This last step is kind of labor intensive if you have a lot of brushes you want to import and it could be streamlined with a batch import/select all to import feature. On several occasions Art Studio couldnt communicate with the File Helper utility, which inevitable required me to close the app and reopen or all together restart. I feel like this was also an issue with the File Helper app, which is more of an iOS bug. Its as if File Helper craps out and cant access any files deeper than the root.
Anyways, it works, but its not the easiest. That said, with this feature and all the other stuff ArtStudio offers, this is hands down the BEST app for drawing on the iPad. I cant believe everything that is on here. Its like the desktop version of Photoshop running on my iPad. Unbelievable.