very large project metadata handling experiences

You don't sound like you have experience with Premiere's designed process for massive projects, called Productions. Which has handled a decent number of major movies, and a ton of episodic and doc work for the last few years.

Do not use the old stand-alone workflow for that. In fact, I even use Productions mode for nearly all my work, in my small shop. So all my b-roll, sound libraries, graphics, template sequences, everything is available for any project for any client/personal need. Without duplications or anything.

It's a very different process though. You tell Premiere to create a new Production, it creates a Production folder on disc, with the prodset Production file inside it.

And you see an open panel. Right-click and build your organization for your project.

Right-click to make folders for basic things like Media, Sequences, Sound, Graphics, whatever.

Inside those folders make subfolders as needed for specific organization work.

Finally, right-click create projects to house things ... similar to 'bins' in the old workflow.

So you might have your Media with say subfolders by day or camera or whatever. Inside those you have projects for specific types of media.

In your Sequence folder, create a new project for stringouts. Grab clips from the Media project, drop onto your timeline. Start your stringout.

And on through the project. No duplication, just ... works.

And the best docuementation Adobe has produced gives a lot of information written well, probably beause Jarle Leirpoll did most of the writing.

Premiere Pro Productions Introduction

Using Productions in Premiere Pro

Adobe Long-form and Episodic Best Practices Guide 

Jarle’s blog expansion of the pdf Multicam section: Premiere Pro Multicam

Hey there,

Thanks for the message. Welcome to the forum. I hope we can find another community member which has undertaken such a large project. Personally, I have a Production, which contains many projects within it. I would say I have hundreds of clips, perhaps thousands, and I have been able to manage this "travel" project as a Production for almost a decade. I would say, set up a Production, and then test to see if your workflow is going to be OK for you regarding your search query. Let us know any hurdles you face. 

Thanks,
Kevin