Cool, looks like a pretty tight gap at the bottom so I wasn't sure.
Good luck fighting with the lack of offset for a few days 
In your opinion, is it hard to get used to the lack of offset?
I was considering getting planck so I wanted to hear some opinions.
I don't think so, it's not so different that it makes it a pain. I've had more issues while coding and remembering where I put [], {}, (), -+=_ etc. With my layout, I used the keys to the immediate left and right of the space key to switch to layers that have those keys, and some of them are in places that I'm not used to. I also ended up making the 2nd key to the left of space enter so I could keep the single/double quote in the same relative position that it used to be so I use my left thumb more often.
The other thing I should point out, is that a friend let me borrow a kinesis advantage for a few weeks which have the linear columns as well, and I was spending some time with that before finishing this build so I might have had some experience moving towards being more linear.
I noticed with the linear offsets, you need less finger motion overall which I believe makes it somewhat more ergonomic. I also switch between keyboards often, so it's not so odd that I can't get back to typing at 80+wpm on a regular keyboard.
I'm considering building more of these because I was in the group buy for the gateron switches, however a friend of mine just introduced me to plover so I'm looking at building something for that soon.
http://plover.stenoknight.com/