Upload restricted by user id

Hi,

Just grabbed your plugin, and it looks great. I wasn’t able to find a way to do this, but might have missed it. Apologies if so.

You can allow access to manager mode by user id – which is amazing and just what I need.

I don’t see a similar ability for the file upload shortcode. I would like to be able to only allow the same user ids to see and use the file upload buttons. It seems like I can only filter by roles and capabilities.

Is that possible? Thanks.