Photos - need set-up help

[rexone]

Ok, Apple is giving us very little choice but to migrate to the truly crappy Photos app from iPhoto as they are slowly hobbling iPhoto so I figure I'll make the move.
Problem I have is this...
I tried it a while back & gave up due to the enormous number of missing features & the truly mind-numbingly bad features so this means that if I open Photos it has my library up to that past date but not a recent version.
So I thought... okay, I'll just flick the various files for Photos I'll force it to start again.
Problem... if I go into my Pictures folder in my Home folder there are 3 x .photoslibrary folders all of which have different creation dates, I'm assuming that this was when I knowingly tried it before.
The most recent folder says it's the same size as my iPhoto library, 1.31Tb.
Now I was under the impression that Photos didn't actually duplicate your iPhoto library, that it just referenced it & started a new one for new additions.
So... why is this Photos library showing so large if it's just referencing (the other 2 are saying they are 956G & 1.3Tb which all actually adds up to more than my hard-disk capacity...)

So... short version...
Can I just drop these in the trash along with any preferences files & then launch Photos to force it to start a new library?

 

[Dave Braine]

Now I was under the impression that Photos didn't actually duplicate your iPhoto library, that it just referenced it

No, that's not true. Once Photos has imported your iPhoto Library, you can safely delete the iPhoto Library file.

Can I just drop these in the trash along with any preferences files & then launch Photos to force it to start a new library?

Yes, but you'll lose any photos that are in those libraries.