Definitely the shorter the better but the URL is too small to be legible at a distance.
I also would like to see a version where the Nostrich doesn’t break the word into two parts. Right now if you don’t know what Nostr is you’d read it as No Str.
Discussion
Here you go #grownostr 
If the goal is that people go on the website, I would actually do it the other way around. The URL in a big bold font in the center, and "Join Nostr" smaller on top.
