Put simply - So easy to remove they fall out. 

UNTIL you put something into them, then so tight they might even hold tighter than the original design.  

How?  Magic of course.

The inserts for attaching to the wall also have the same cuts to allow them to expand, effectively locking it together, but when the screw is removed, they can be removed too.  

Now-- File explanation

Loose is referring to the INNER hex, not the outer.  They are all loosey goosey in the honeycomb.  But not all designs found on the world wide interwebs have consistent hex sizes, some are a little larger than RostaP designed, some a little smaller.  
So I made Loose to account for them, but I found Loose to be fine for everything, so I personally put all my hex's in the loose hole.  

So, start with loose, and if you like that tighter feel, try the other.

Oh, I am happy to customize this – just ask.
The source though, I am NOT happy with that embarrassing workflow, so don't ask.

Update and Warnings

Find me on Discord

I am not really responsive here, I will be better there.
https://discord.gg/uvvBPey2

Step Files

Yes

Hex Connector

So with everyone's printers being different, and different plastics, tolerances can never be assumed to be perfect.  But.  I wrongly assumed the amount of difference that I should account for.  The issue is, I am not sure how to tweak them for you.  So please, hit me up on Discord, I will work with you directly to make a variant that suits you, and share it here for everyone to have access to.
But I have included a TIGHT how.

Wall Connector

So the wall connector breaks for many people, so that should probably be used with caution. 
I did all mine in PETG because I do not trust PLA to be under force for extended periods, and sure enough, it broke.  Funnily I am not concerned as the screw will hold it in place, but it is no good regardless.  The solution is simple, do not allow it to flex so much.  The issue with that, ease of removal is gone.  I am confident a happy middle ground can be found.   
So a heads up is indeed needed.  If you know how it should be tweaked please hit me up on Discord, and I can work directly with you, and share it here for everyone to have access to.