Number 3 is almost the same as my 40%, ut47.2 . And i have a hard time adjust to it, more than i would think. The even stagged thing is hard for me to get used to. I think if you devote your whole time using it then you would be fine but i keep going back and forth.
And for this last layout, please ask your friend where does he normally press the spacebar? The layout may not make it look like much but actually the spacebar is way over to the left so if he has the habit of pressing space on the edge by right thumb like I do, he would have a very very hard time typing on this since spacebar is way out of reach.