Storing GoPro footage without wasting space converting it?

Hey, I have a 2011 MacBook Pro with a 1TB SSD boot disc and a 1TB media drive.

I'm fairly mobile, so don't want to carry extra hard-drives, beyond the 4TB backup disk I already take.

I initially used the GoPro software to convert my files, as it suggested; before realising it was taking 6GB of video footage from a snorkel drive or surf session and making it many times larger; when it's actually a minority of shots I'll ever use.

Likewise, if I dump it all in Final Cut Pro X then it seems to make converted copies, which both absorbs a lot of time on my ageing processor and takes up way more space.

Therefore, I cut my GoPro MP4 videos straight off and paste them into folders in OSX, but then don't have any tools for tagging them etc.

What would you recommend?

Is there a way of putting them into Final Cut Pro X in a way that doesn't result in multiple copies being made/converted, until I actually make a film?

Thanks

First, I'd not convert them at all. I edit tons of GoPro and Osmo footage daily, always keep it native, never optimize. Since I'm working in an office, once the camera cards get to me, I import, copy to Library, then erase the cards. We have a backup of the RAID I work on, so I don't worry. And I only have one copy, in native format, of my clips.

In OS X, you CAN in fact tag footage, give it keywords, etc. Right-click and just above the colors you can assign to it (which FCPX will make keyword collections out of) is an option for "Tags..." That will let you assign keywords that FCPX will recognize and use. FCPX can also use Folder names as keywords. We use all of this to organize footage when shooting on location. Then when we import into FCPX, most of the organization is done already.