Yeah, you just select pin pitch and ring sizes in the Inspector for the header.
0.3mm I don't know, but there isn't much holding it down. Maybe a smaller hole as the pin is 0.4mm.
I like to see a black line between 5V/GND and the IC, it makes me feel better.
Even the other side of the chip I would come out 1 grid so I can see the connections better.
Be careful when you join to a junction. I usually grab the junction and move it around to make sure everything is connected - you have to do it anyway because it looses the snap -.